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Engine Control Module and Sensor Locations


I like to write about automotive topics—particularly DIY stuff and auto concepts.

Mercedes Benz Engine

Mercedes Benz Engine

The engine control module (ECM) is also known as the powertrain control module (PCM) or the engine control unit (ECU).

The main responsibility of this controller is to get information from sensors and run certain actuators. In the case of any errors, the ECU shows a check engine light on your dashboard.

We will discuss where and why sensors are placed in certain positions and give some insight as to how or what the sensors sense. If you are a DIY person, then you could even open up the sensors yourself and clean them for optimum signals to reach your ECU.

Powertrain Control

Engine Control Module

No matter how complicated, you'll find the sensors below in any EFI engine:

  1. Engine coolant temperature
  2. Air temperature
  3. Barometric pressure/manifold absolute pressure
  4. Mass air flow
  5. Idle air controller
  6. Crankshaft
  7. Camshaft
  8. Throttle position
  9. Oxygen
  10. Knock
Engine coolant temperature sensor

Engine coolant temperature sensor

Location of ECT sensor

Location of ECT sensor

Engine Coolant Temperature Sensor (ECT)

Like humans, a vehicle needs to maintain a specific temperature in order to function properly. Too cold, and the vehicle will drink too much petrol. Too hot and the head gasket could leak. Coolant is a liquid used in the vehicles radiator of the car to maintain the temperature at which the engine can perform at its optimum.

The engine coolant temperature sensor simply tells the car's computer (ECM) the current temperature of the vehicle. When the temperature of the coolant reaches between 75 and 95 degrees (depending on the manufacturer specifications), the ECM instructs the radiator fan to turn on and start cooling down the liquid.

  • Usually it is located either on the bottom of the radiator, or by follow the top radiator hose towards the engine block. You'll see it on mounted on the engine block.
  • It can be cleaned using a wire brush when you entirely change your engine coolant (approx. every 80,000 km or 50,000 miles).
Intake air temperature sensor

Intake air temperature sensor

Location of intake air temperature sensor

Location of intake air temperature sensor

Air Temperature Sensor (IAT)

The intake air temperature sensor (IAT) tells the ECM the temperature of the air that is going into the engine. The cooler the air, the better the performance of the engine, which is probably why you might have noticed a difference in the car's performance on a summer night as compared to the day.

  • It is usually located on the air filter box or the pipe going from the air filter box to the throttle body. Toyota has a MAF and an IAT sensor built in one unit which has five wires located on the air filter box.
  • It can be cleaned once every six months (depending on dust/pollution), using carb cleaner on an ear cleaner.
Manifold absolute pressure sensor

Manifold absolute pressure sensor

Location of MAP sensor

Location of MAP sensor

BARO/Manifold Absolute Pressure Sensor (MAP)

The baro sensor measures the ambient air pressure, which tells the ECM the current altitude of the vehicle. If you're driving in the mountains you'll need less fuel, because there is less oxygen in the atmosphere and therefore less oxygen in the engine cylinder. The ECM will adjust the fuel injectors "throwing time" or pulse width accordingly.

The map sensor detects the vacuum pressure created inside the intake manifold of the vehicle and sends the engine load information to the ECM. The ECM will adjust the fuel injectors pulse width accordingly.

Note: Baro and MAP sensors look and work in a similar fashion, therefore only one of the two sensors will be found in one engine.

  • Usually found either bolted on the intake manifold or linked with a vacuum pipe from the intake manifold.
  • If mounted on intake manifold then should be cleaned every 6 months to 1 year, using carb cleaner (depends on fuel quality where you live; the lower the quality of fuel, the more carbon deposits found). I've had to clean some every three months.
Mass air flow sensor

Mass air flow sensor

Location of MAF sensor

Location of MAF sensor

Mass Air Flow Sensor

The Mass Air Flow sensor is responsible for measuring the volume of air entering the engine.

The sensor contains a heated sensing element, as shown in the picture above. The temperature of this element has to be kept constant, but is cooled by the air passing through the intake. The MAF sensor produces more current to keep the temperature at the level required by the manufacturer. There is a small computer in the MAF which calculates the internal current flow to heat the element, and by using this figure it can calculate the volume of air going into the engine as well as the air density and temperature. The ECU uses this information to adjust the injector pulse width and spark (ignition) timing.

  • The MAF Sensor is located either on the air cleaner box or along the pipe going from the air cleaner to the throttle body.
  • Note: Since the MAF sensor calculates the air density, the engine does not need the MAP or baro sensor readings. Therefore you will not see a MAP or baro sensor in your engine if you have a MAF installed and vice versa.
  • Can be cleaned with carb cleaner or MAF cleaner spray and ear cleaning bud. Clean if you see dust or carbon deposits.
Idle air control valve (Japanese makes).

Idle air control valve (Japanese makes).

Idle air control valve (seen in Hyundai models).

Idle air control valve (seen in Hyundai models).

Location of IACV on typical Japanese vehicle.

Location of IACV on typical Japanese vehicle.

Idle Air Controller (IACV)

The Idle Air Control Valve (IACV) is responsible for keeping the RPM of the engine steady. The IACV is actually an actuator and not a sensor because it does not supply readings to the ECM, but works on the command of the ECM. I just added this actuator for the DIY enthusiast.

There are two coolant pipes connected to the housing, which you can see on the far right of the picture shown. The black piece shown in the picture is a magnetic actuator which rotates the valve shaft allowing it to open and close as required by the ECM.

Whenever you start your car the IACV will increase the RPM until the coolant temperature sensor (ECT) tells the ECU that the temperature of the engine is up-to the manufacturers specifications. The RPM will then drop down to and remain steady at approx 800 rpm whenever there is an extra load on the engine the idle controller adjusts and compensates for the load applied—for example, switching from park to drive mode in an automatic transmission vehicle, or even when you switch on your air conditioning. You can also adjust the idle speed of the vehicle by loosening the screws on the actuator and rotate the actuator. The default setting of the actuator is normally in the middle.

  • Located on the throttle body of the vehicle.
  • Depending on fuel quality, carbon deposits build up and the valve shaft gets stuck resulting in fluctuating RPM signals on the dashboard.
  • To clean remove the black magnetic actuator which will reveal the shaft. Try rotating the shaft with your fingers. If it's a little hard, then use carburetor cleaner and a toothbrush or ear cleaning bud to clean the area of the valve (the two identical rectangular blocks), and check to see if the shaft is easy to rotate. When putting the magnetic sensor back, make sure the rubber O-ring goes on the metal housing and then align the tip of the shaft with the step inside the magnetic sensor. Set the sensor to the mid-position and tighten the screws.
  • Note: On some vehicles a scanner is required to reset the idle controller once opened.
Throttle position sensor.

Throttle position sensor.

Location of throttle position sensor.

Location of throttle position sensor.

Throttle Position Sensor (TPS)

The throttle position sensor (TPS) is linked from the accelerator pedal to the throttle body.

The TPS tells the ECM that the driver is pressing the accelerator pedal. The ECM can also verify this information with the MAP or MAF sensor readings, thus increasing the injector pulse width and spark (ignition) timing.

  • The TPS is located on the throttle body. Honda has an adjustable TPS sensor and if the initial if your RPM is high and cannot be controlled through the IACV, then the voltage readings of the TPS should be checked. The normal reading for a Honda is close to 0.6V at idle.

I remember playing with the TPS in my friend's car and adjusting his TPS to about 2.5 volts at idle. The result: The became a gas guzzler, consuming about 30 litres of petrol (about 7 gallons) in 30 km (about 18 miles). I guess we learned the hard way.

A newer system for the throttle control came in 2003-2005 and newer models of vehicles, in which a throttle cable is no longer used. A sensor has been placed in the accelerator pedal and the TPS sensor has been replaced with a throttle position motor.

  • This sensor never requires cleaning. If you do want to clean something on it then just clean the connector points with electrical contact cleaner and a toothbrush. That goes for all the sensors.
Camshaft position sensor.

Camshaft position sensor.

Camshaft Position Sensor

The camshaft position sensor (CMP) is electro-magnetic and produces a voltage when a metal object moves past. This sensor is responsible for telling the ECM the current position of the camshaft. With this information the ECM can calculate which valve is open and throw fuel through the injector into that cylinder.

  • This sensor is found on one end of the camshaft, usually on the right side in a front wheel drive car. It's normally not very difficult to access.
  • Cleaning can be done with a simple dry cloth, but if the oil has been used for too long, a golden-brown stain is left on metal portion of the sensor. In some cases it even comes out black and gooey, which is basically old engine oil turned into sludge. if it's stained then you can use a wire-brush or very fine sandpaper to remove the stain. Make sure no metal bits remain on the sensor. If you need some liquid type material to get some stains off, try WD-40.
Crankshaft position sensor.

Crankshaft position sensor.

Comparison of CMP and CKP sensors.

Comparison of CMP and CKP sensors.

Crankshaft Sensor (CKP)

This sensor is very similar to the cam position sensor in functionality. It is responsible for telling the ECM the exact location of the crankshaft as well as the RPM (rotations per minute) of the engine. With this information the ECM knows the position of each piston in each cylinder. Using the cam sensor readings, as well as the crank sensor readings, the ECM knows exactly which injector needs to be activated. The synchronization of the cam and crank shafts in an engine is the key to engine performance. This synchronization is also referred to as the engine timing. With the correct timing you will get the fuel and spark delivered at the right time.

  • It is located at the bottom of the engine somewhere close to the crankshaft.
  • Cleaning technique for this sensor is exactly the same as the cam sensor. Cleaning once a year is good enough for this sensor.
  • Note: If your car does not start, a possible reason could be a faulty crank sensor or a broken wire in the crank sensor circuit.
Oxygen sensor.

Oxygen sensor.

Oxygen Sensor (O2)

The oxygen sensor (O2) is responsible for "smelling" the exhaust fumes and detecting the oxygen content in order to make sure the engine is consuming the right amount of fuel. The ratio maintained by the ECM is 14.7 parts air to 1 part fuel. This is known as the air/fuel ratio.

There are two types of oxygen sensor: zirconia or titania. These are materials which can detect oxygen and produce a voltage. The voltage range falls between 0.1V to 0.9V.

I normally use a vehicle scanner to check the maximum and minimum readings of the oxygen sensor. If I see both peaks, then I know the sensor is working fine. If the voltage max is 0.8 then I open up the sensor for cleaning. Sometimes the sensor produces a constant voltage but does not fluctuate. This generally means the sensor needs to be replaced.

Knock sensor.

Knock sensor.

Knock Sensor

The knock sensor contains a piezoelectric crystal. This crystal is able to detect mechanical stress and produces a voltage when the car knocks or pings. Under heavy acceleration, it sends signals to the ECM and the ECM retards the ignition timing to compensate for the knocking, which in effect protects the pistons and rings from damage.

Knocking also occurs when using low-grade fuel and having the knock sensor allows you to use different grade fuels without causing engine damage.

  • This sensor is normally bolted onto the main-body of the engine in the most difficult and awkward positions. Lucky this sensor never requires cleaning.

What Happens If One of These Sensors Fail?

If a sensor fails and gives abnormal readings, for example a coolant temperature sensor giving a constant reading of -40o, then the ECM goes into fail-safe mode. This means it basically ignores the values of the sensor at fault and tries to either calculate the value of the failed sensor or assumes a constant reading so the vehicle can keep running. Some faliures like a crank sensor or a MAF sensor will result in the vehicle not starting at all.

This article is accurate and true to the best of the author’s knowledge. Content is for informational or entertainment purposes only and does not substitute for personal counsel or professional advice in business, financial, legal, or technical matters.

Questions & Answers

Question: My car is mark 2 2.0cc .2002 model. When I start it, I notice a smell of fuel and the fuel consumption is a little high. What can I do?

Answer: Check for leaks in fuel rail

Question: My Toyota Auris Rx 1.8 2009 model cooling fan or thermal switch does not run whenever my engine is on and even when I drive but my temperature never overheated why is this?

Answer: The cooling fan works with the thermal switch. The thermal switch will have a certain point (I.e.93 degrees Celsius) at which it will enable the current to the cooling fan. Your vehicle also has a thermostat valve which allows for the rotation of coolant within the engine. This valve also has a set temperature at which it will open to allow the cold coolant to enter the engine.

Now if you have a thermal switch which is set to run when the coolant reaches 93 degrees and also have a thermostat valve that allows for the rotation of coolant at approximately 87 degrees then the vehicle does not need the fan. It will only engage in very hot weather where the radiator cannot cool the contents (coolant) quick enough.

Question: What allows for an engine to be diagnosed?

Answer: Any malfunction in the sensors or mechanical issues.

Question: After cleaning my 1999 Honda Accord 4 cylinder 2.3 l VTEC all the carbon out of the intake system. My car starts to run, then stalls out and will not start back up. What's the problem and what should I check?

Answer: Check MAF / MAP sensor electrical grip (whichever your car has) and look for air leaks.

Question: I am in the UK and have a Seat Leon with 1.4tsi 150bhp. If I drive off in the morning, the engine warning light comes on after about 5 mins. The code reader shows fault code PO11F re ECT sensor. Can this be erased & not come back until next day? The car otherwise runs fine. If I start and then stop before driving off in the morning, the warning light does not come on at all. I'm wondering if the fault could be related to an ECU remap I did. Firm that did the remap is adamant that the fault isn't related. Is that true?

Answer: PO11F In most cases seems to point toward emissions rather than the ECT. Even though the vehicle shows and ECT error there is an underlying problem which will not fix the problem even if you change sensors. I would say first, check the fuel pump pressure when you turn they key in the ON position (priming; without starting the engine). Second; check if your Catalytic converter is choked (if you have problems with fuel consumption). In another source, the code given is associated with overheating and a blown head gasket or even a minor timing belt issue. It could be one of these but cannot be confirmed as I’m not entirely sure what the remap includes. Try to eliminate the easier ones to see if it works. If the easy ones don’t do it then wait until the light stays on longer and comes on more often to check the rest.

Question: Is the controller for the heater on an O2 sensor in the ECM?

Answer: Heater location is inside the O2 sensor. Heater is controlled by the ECM so there would be a chip on the ECM board that would control the O2.

Question: My 2010 Ford Mustang 4.0 is hiccuping, jerking, and it feels like it’s hesitating to accelerate. When I’m making a complete stop the car will shut itself off. Why is this the case?

Answer: Look for air leaks in the intake area.

Question: My Nissan sunny 2004 model cranks but does not pick up and the injectors do not spray fuel. What can I do?

Answer: Change CAM sensor and try.

Question: Can my 2000 Toyota car without a camshaft sensor make itself consume fuel? Can I clean the exhaust sensor to make it work again?

Answer: If the exhaust sensor is dead it will not work again. If the readings are not in the correct range then cleaning can improve it. Excessive fuel consumption is only if the MAP sensor has stopped working. You will see black smoke come out of the exhaust if that is the case. If that is not happening then your fuel filter could be choked and needs replacing or valve clearances need to be checked especially on the exhaust side.

Question: Can you tell me where the ECM is on a 1984 Pontiac 6000?

Answer: Not exactly sure. Some sources say in the air filter box in the engine bay and others say in the dashboard. You could follow the sensor wiring loom to get to the PCM.

Question: how can I tell if the knock sensor is faulty?

Answer: You will get a check engine light which will indicate it is faulty. If there is no indication then it is fine and the problem is somewhere else. If still in doubt then replace it.

Question: My Cadillac cts 05 has a code reading u0100 and check engine light and will not go over 2rpm would like to know what's wrong?

Answer: A bit of a serious issue with either the wiring or the control module. The ECM cannot pick up signals from either the engine or the transmission modules.

A rat could have eaten up the wires or the connections may be loose. You will have to trip the carpet and follow the wiring to make sure it’s all good. If all good then try changing the controller units. Continuity test between the cables to find faulty cables. The problem lies in the main network of cabling; not the sensors. It will continue to stay in limp mode (2mph) until the issue is fixed.

Question: Is a sensor & module for the transmission considered the same part?

Answer: No. A module is a separate ECU that controls the transmission. Sensors give the module information. Have a look at the transmission control module article I have written to get more info on the types of sensors used with the transmission control module.

Question: We had some trouble codes leading us to fix our TPS and IACV but we still have black smoke and high idling and occasionally stalls. No trouble codes now, any idea which direction to take?

Answer: Confirm the TPS is installed properly. Sometimes it does not rotate if in the wrong position. With the ignition on press, the accelerator pedal and either use a multimeter on the sensor wires or using a scanner make sure the voltage is approx 0.6v with nothing pressed then press the accelerator pedal to “wide open throttle” position. At wide open throttle, it should be approximately 4.5volts. If these are correct then Make sure IACV is set to the middle point of the 2 screws making sure there are no air leaks in the throttle area. You can use some silicone to ensure that.

Some vehicles (like Chevrolet) require a throttle reset through a scanner. It will never run properly until you reset using the scanner. Taking the battery terminals doesn’t work either.

If everything is good and still have black smoke then try replacing MAP/MAF sensor. that should cover it. If problems persist then send me an email with a snapshot of diagnostic voltages at idle (running engine) and another snapshot after quick heavy revs... it gives the max and minimum of each sensor which is what I would like to look at.

Question: My Toyota Camry's (2004) temp gauge always go halfway and never go higher even my Cooling fan failed. So I test my coolant sensor by an Ohm meter and the sensor terminal Voltage by Voltmeter and the reading is ok. Is there a possibility that the ECM reading is offset and need to be calibrated?

Answer: If the reading is ok then keep using it. The Camry has a large radiator which allows for natural cooling; this is why the fan doesn’t always go on.

If your water levels are stable in the cooling system then I would suggest leaving it as it is.

Question: If my temperature gauge is not working at all does this mean all the sensors have problems?

Answer: If the temperature gauge or any sensor fails you will get a check engine light. When this happens the car uses default values set by the manufacturer.

Question: 1999 Vauxhall Corsa 1.2 16v not revving past 3000 rpm, Sounds like it's revving of the limiter, but only at 3000rpms, what could cause this?

Answer: Sounds like the ECU is keeping the car in limp (safety) mode. You need to check with a scanner to see what could be causing it. Sometimes it’s the oxygen sensor, other times it could be the injectors.

Question: Other than engine sensor signals, name three other inputs signals an engine control module might receive?

Answer: Turbo, Evaporative emissions control, vtec solenoid, oil control valve.

Question: My land cruiser shows a code 1421 with autel (master cylinder scan, cylinder pressure sensor). Where is the location of this sensor?

Answer: On the brake master cylinder. Look for grips near the brake fluid reservoir. It could be a broken wire, or the grip may not be on properly. If everything seems ok then try replacing the sensor.

Question: What would keep the check engine from coming on in a 97 Dodge 5.9?

Answer: It could be anything; you will need to get it scanned to get the code.

Question: How should I troubleshoot a changing sound from the mainfold and a bad sound on the top?

Answer: Check for air leaks.

© 2012 Irfan


quddusadvocate on July 08, 2020:

my corola a4 sleeps while running and ignites at onece/

what may be the problem/s

Irfan (author) from Adelaide, Australia on May 18, 2020:

@Hambondatu ;

Check your valve clearances also known as rocker arms or tappet adjustments. Make sure the gaps are correct for all the valves.

Hambondatu hambombari on May 18, 2020:

I'm having a Toyota 2.7 3rz engine and it doesn't want to start morning hours

Irfan (author) from Adelaide, Australia on January 31, 2020:

@zagi; when the temperature is high it usually points to faulty coil packs ... you may want to swap and check them before buying a new set. This usually starts with missing at higher temperatures and ends with stalling. Another reason could be the fuel pump heating up and causing the stalling. Replacing the fuel pump will solve this. Also check the coolant and air temperature sensor readings to make sure they are working in an acceptable range. If not then clean; if still causing trouble then replace.

Zagi on January 31, 2020:

My Toyota Vista Ardeo has been stalling on the road especially when the temperature is high. Is it the problem of sensors. Kindly help

Irfan (author) from Adelaide, Australia on January 10, 2020:

@toby ; please send the error codes you are getting. I can help more precisely if I know the codes.

Toby Howard on January 10, 2020:

I am having problems with my 2013 Ford F150 3.5L V6 EcoBoost. Having problems with idling, loss of power, fuel economy loss, overall bad performance. I am a diy person so did some diagnostics for

codes it threw like mapcenters, high pressure fuel pump, oxygen sensors, etc. Also had gas in crankcase.. I have replaced all 4 oxygen sensors, I have replaced all 3 map sensors, I have replaced high pressure fuel injector pump and I just put a salvaged ECM in it and had Ford dealership reprogram it for my truck and it through 13 more codes like multiple cylinder failure and some of the same codes for things that I have already replaced. I'm thinking injectors are stuck open but not really for sure and that has been my problem thus far. Have any insights that could help?

Irfan (author) from Adelaide, Australia on December 17, 2019:

@Ramiro : I only have data for the 1.4, 1.6 and 2.0 Mazda 3. In the 2.0 version the TCM is inside the ECM. So basically one controller for both engine and transmission. Hope that helps.

Ramiro Rodriguez on December 17, 2019:

I have a 2005 Mazda3 with a 2.3 engine, the problem I’m having is that when the AT light come on the transmission do not respond well. Other Mazda3 have a TCM located under the battery box but no this one, .

My question is. Where is the TCM located on this vehicle.

Irfan (author) from Adelaide, Australia on November 17, 2019:

@fred; the rpm signals come from the crank sensor. Somewhere near the crank shaft. Usually has a thick black coating with two wires in it.

Fred on November 17, 2019:

Hi can you tell me we can i find the tacho signal wire for a ford ka 1.3 2006

Danie on September 29, 2019:


Irfan (author) from Adelaide, Australia on September 03, 2019:

Hi Mehran,

Sorry I’m not sure which radar sensor you are looking for.

Mehran on September 03, 2019:


Where locate sensore radar in toyota corolla?

Irfan (author) from Adelaide, Australia on May 31, 2019:

@Kolopen brown;

Check for the following

battery is fully charged and engine cranking normally. If not; check starter motor.

Immobiliser issues

air blockage in the intake system.

Air inside the fuel system (requires bleeding)

Low fuel in tank

Pre-heating system (glow plugs)

Exhaust blockage (CAT)

Clean crankshaft sensor

Kolopen Brown,email-bkolopen@yahoo.com Lombrum Manus Island PNG on May 31, 2019:

2016 Ford Ranger 2.2l crank,can not start.Can I remove and clean the

crankshaft sensor/cam sensor.

Irfan (author) from Adelaide, Australia on April 26, 2019:

@jimmy; check the wiring for signs of corrosion or rust. Make sure you clean the grips and points with an electrical contact cleaner spray. Try adding an earth wire to the ECU box. If none of these work then look at replacing the ECU. you could also test with a similar vehicles ECU before purchasing a brand new one or just get it from the wreckers.

Jimmy on April 26, 2019:

I was scanning my smart forfour .and i got trouble code P0606 ECM .should i change complel ECU and prograim it .or chech the wires ?

Irfan (author) from Adelaide, Australia on March 06, 2019:

@joseph : need to replace the MAF sensor.

Joseph on March 06, 2019:

I have nissane almera 1.6 2004 problem is idle and smoke black

Nithish on February 20, 2019:

Super boss

dejene on December 27, 2018:


Irfan (author) from Adelaide, Australia on December 12, 2018:

@jamal: cleaning works. I also used throttle body spray to clear the carbon inside the metal shell. Try cleaning before replacing.

jamal on December 12, 2018:

do i need to change oxy sensor or its enough to clean it by steel brush. its santafe

Hassan on October 22, 2018:

Nice good

Zaffar Abbas on October 21, 2018:

My sweet friend thankyou

Irfan (author) from Adelaide, Australia on October 14, 2018:

@zahid: In your registration papers or the metal vehicle identification plate under the hood.

zahid on October 14, 2018:

how can I get engine code or model of my ecm, where it is written on?

Irfan (author) from Adelaide, Australia on October 11, 2018:

@zahid : check the sensors with a scanner. If no error codes then all the sensors are working fine. You can find the wiring diagrams online but need to know your engine code.

Zahid on October 11, 2018:

my Honda 2000 city has an altered arrangements having ECM with too many wires are not being used. I want to check its wiring case I am feeling some problems in its drive. Please help me for the following,

1. wiring diagram

2. how can I test/check my car's sensors

My ECM has ear a no as LOX 7748

Irfan (author) from Adelaide, Australia on October 10, 2018:

@jimmy : those are coils or coil packs. They are not sensors; which sense things but actuators which can do a single task (create spark) and are told by the ECM when to do it depending on a few other readings such as the timing etc.

Jimmy on October 10, 2018:

What is the Sensor called what gos on the spark plugs

Irfan (author) from Adelaide, Australia on October 07, 2018:

@kanisha : one possibility is that the timing belt/chain has skipped a tooth causing these issues. You will have to get that checked first before thinking about other things.

Kanisha on October 07, 2018:

Everytime the check engine light comes on it says PCM or all cylinders are misfiring can you please tell me why?

Irfan (author) from Adelaide, Australia on September 24, 2018:

@Itumeleng: check air/spark/fuel supply.

Itumeleng on September 23, 2018:

Hi my Toyota quantum 2kd engine cranks but no start

Irfan (author) from Adelaide, Australia on September 14, 2018:

@saad : no related videos

@Iter : thank you.

Iter on September 14, 2018:

This is a very good idea to learning car system.

Irfan (author) from Adelaide, Australia on August 26, 2018:

@ajay : it depends on the vehicle and their features. You will find these sensors in every efi vehicle as these are the core sensors to keep a vehicle running.

ajay on August 25, 2018:

good job

but its not a complete list.

more then 55 sensors use in vehicle.

georgezuze on August 24, 2018:


Arvind on August 10, 2018:

How many types of sensor in vtvt engine

Arshad khan on August 09, 2018:


Irfan (author) from Adelaide, Australia on August 02, 2018:

@Nagvadiya: maybe fuel pump overheating. Need replacement.

Nagvadiya hitesh on August 02, 2018:

Why not start my car in hot conditions??

chibwebrian9@gmail.com on July 17, 2018:


Musadaq Javaid Chaudhary on July 13, 2018:

good information about function & location of sensor.

Irfan (author) from Adelaide, Australia on July 02, 2018:

@mubeen : as Goose mentioned. Check for air leaks. Next try high octane fuel.

Irfan (author) from Adelaide, Australia on July 02, 2018:

Hey George,

Great to hear from a fellow Zambian... I miss that place.

I’m guessing your closest option would be South Africa but it would be helpful if you can take the computer to an electronics guy and try to get it repaired. The chips on them are similar to other Toyota computers so you might be able to get one from a wrecked car. The most common problem in toyotas were the injector chips got burnt. You can replace them with other Corolla models. Hope that helps. Ping me again if you need more details.

George on July 02, 2018:

My 2002 toyota duet EJ-VE engine computer box got damaged. Where can i get a new or used one.in zambia there are not found.its an M30

Goose on April 29, 2018:

Maf-intake hard rubber flex duct vacuum leak...there can be NO leak between MAF and engine block or this happens, wrap that rotten ribbed section with some duct Tape. God Bless!!!

Mubeen on April 22, 2018:

My engine starts to knock at 3500 rpm. It used to knock at 7200 rpm

D17 A civic 2005

Solution please

Irfan (author) from Adelaide, Australia on April 19, 2018:

@damilare :

Step 1: Set the engine switch to the "LOCK" position with trip meter A reading shown.

Step 2: While pressing the trip meter reset button, set the engine switch to the "ON" position.

Step 3: Continue to press and hold the button until the trip meter displays "000000" till all 6 "0" clears.

damilare on April 18, 2018:

my Toyota big daddy shows oil light on the dashboard when it's hot meanwhile I changed oil pump, oil filter with new oil. please help I don't no what to do

Irfan (author) from Adelaide, Australia on March 21, 2018:

@Clive : you can’t blow the ECU like that. Sounds more like your immobiliser with the keyfob May need reprogramming. Get that checked first. Engine light stays on at ignition. It will switch off once the vehicle starts and it checks if all systems are ok.

Irfan (author) from Adelaide, Australia on March 09, 2018:

@letsela; check MAF sensor area and intake pipes for air leaks.

Irfan (author) from Adelaide, Australia on January 22, 2018:

@rajesh ; try changing the temperature sensor also know as fan switch.

@stompi ; follow the top radiator hose, it will lead to the thermostat valve area with a few pipe connections; you might find the sensor there.

@johnny g ; could be one of many things. First check security system and make sure immobiliser is working ok. Second check the battery voltage. In the newer cars if there is not enough juice in the battery it won’t start, I think 11.5volts is the minimum. Next check for air leaks in the intake area. Next check If the injectors are working or not; next check if you have a spark or not. Next check engine compression. If all is fine then try changing the crank sensor and if it has a MAF sensor then you may have to replace that too. Better if you can test the parts with a friend’s car or something before actually purchasing. Let me know if there is anything else.

johnny g on January 21, 2018:

2008 mazda 6 2.3ltr engine wont startperiod could it be the crank sensor

stompi on January 17, 2018:

I'm driving 2001 jetta 4 1.6 SR engine I just put a radiator but this one don't have a temperature switch on top of it so I like to know whether dose this model have a temperature switch from engine like conquest 1.3

Rajesh Sharma on January 13, 2018:

Toyota haice. ..2005 ...EFI. ..2.5 turbocharged diesel .radiator fan runs ok ..on direct but doesn't start when temperature raises to operating temp ....cannot figure out sgars wrong ...also give rough engine .. srarts ok ..

Irfan (author) from Adelaide, Australia on January 03, 2018:

@Jeffrey : sounds like your throttle position sensor is not on properly. Located on the other side of the accelerator Cable ... you need to check the voltage it’s giving out and keep it somewhere around 0.5volts on idle. 4.5volts on wide open throttle.

Farhan on January 03, 2018:


Jeffrey on January 02, 2018:

I have a Toyota camry 3s fe engine done engine overall a couple of days ago but ever since that day the fuel consumption became high now takes 1 litre for 3 km which is very and extra bad for a 2.0 engine the power is good no doubt but it sometimes hunts while idling and sometimes the check light is on. Most of the times I notice black smoke what might be the problem

Irfan (author) from Adelaide, Australia on December 18, 2017:

@Rajesh : you might have to replace the engine coolant temperature sensor. Follow the radiator pipes to the thermostat valve; there will be a 2 wire sensor in that place. also known as the fan switch.

Rajesh Sharma on December 18, 2017:

My toyota hiace With a 2 kd ftv diesel engine fan does not start when engine gets hot ..but both fans are ok ..the relay and fuses seems all ok ...will appreciate. .thanks .

Irfan (author) from Adelaide, Australia on December 13, 2017:

@addis : you cannot use one ECM to test. You will need to use the ecm for that specific engine. It will have to change every time.

addis on December 13, 2017:

how to use one ECM on engine test stand for different types and models cars??

Irfan (author) from Adelaide, Australia on October 31, 2017:

@sazi : check for air leaks. That’s what causes heaviness... also check idle controller on throttle body. If problem persist then get the air sensor checked again.

Sazi on October 31, 2017:

Hi i had a problem with my nissan almera 2002 model 16 valve,the airflow sensor was giving me problems i had it replaced,now my car is heavy on fuel and idling is going up and down...and my exhaust is smelling fuel when idling by when I took that airflow sensor plug is running 100% bt gives me warning light...can u please help me.

Irfan (author) from Adelaide, Australia on October 26, 2017:

@maizan : you can try to connect a fuel pressure sensor with a meter for viewing. If the pressure drops there is a leak. You can connect it to the fuel injection rail. If you still have problems I’ll add you on whatsapp... let me know.

@his detinedzs: efi did not come out in 1991... please check your distributor or current going to coil pack.

@peace: check crank sensor if it’s an efi vehicle for starting issue.

Azhar on September 22, 2017:

very informative things this side told me


His Destinedz on September 20, 2017:

My 1991 Volvo Do Not Spark At The Coil And 4 Plug

Peace on September 16, 2017:

My Toyota 1996 model, I was going to working one morning and all of a sudden it start jucking and the check sign came up, as well as it won't quick start, I have changed my fuel filter and bump but still, pls what can be the problem. Thanks

DIDIER on September 14, 2017:

thank you for the sensors

Irfan (author) from Adelaide, Australia on September 10, 2017:


Sounds like your idle air control valve needs cleaning. Ask a mechanic to clean the throttle body and idle control valve. It should be ok after that.

Anietie Joseph on September 10, 2017:

Am having some problem with my 2005 Toyota corolla, 1NZ engine. While driving I notice the rpm malfunctioñing, I pull over to çheck, suddenly the compressor discharge some gas, there after I drove it home safe, just at home the engine off. Since then, its has been starting and off, ,call an electricians to check, nothing has found faulty so far, but the last thing to check is the crankshaft sensor or so, pls any one with useful solution can help.

Tharngel on August 29, 2017:

Why does occur tapping noise in VVTI 1300 cc ?

I made modified air flow !

How fit it ?

eufrocinio dantes on August 22, 2017:

Can't locate exact location of the fuel pressure regulator, thanks.

Irfan (author) from Adelaide, Australia on July 17, 2017:

@Rahul : please give more details. I'll try to help as much as I can.

@Billy : sometimes simply unhooking doesn't work. You might have to put a wire to connect both points on the grip you removed to get it to work. Depends on the circuit used in your car. Try putting in a jumper wire and see if the fans work.

BILLY on July 16, 2017:

MY COOLENT FANS WONT COME ON. I unhooked my temperature sensor and they didn't come on then I hooked them back up and turned AC on and they still won't come on changed relays and checked fuses they are all good just wondering what the problem could be?

Rahul jha on July 14, 2017:

Hello sir,

I have a problem my Skoda fabia is late staring problem. Would u like to help how to fix this problem.

Irfan (author) from Adelaide, Australia on June 28, 2017:

Hi Geven,

You will need to get your key programmed to work with the immobiliser of the vehicle. Look for someone who does key programming in your area.

Irfan (author) from Adelaide, Australia on June 22, 2017:

Hi mark,

Try checking the map/baro sensor grip first to see that it's connected properly. Secondly check to make sure there are no air leaks in the intake system. There is also an o-ring on the map/baro sensor ... make sure the sensor sits tight in it's place. If all good and problem persists then you may have to replace the sensor.

It would be better if you can find a similar vehicle and change the map sensor to see that it takes the problem away before purchasing a new one.

Let me know if the problem persists after all this.

Irfan (author) from Adelaide, Australia on June 20, 2017:

hi simon,

i'm guessing your problem will be in the MAF sensor or the MAP sensor. I would advise to get the car scanned with a diagnostic tool to confirm; then replace the sensor.

@donald : did you mean knock sensor?

Simonngwezhi@gmail.com on June 20, 2017:

My car it's producing blacksmoke and engine light is on. It's a 3s engine light diagnosis

donald on May 12, 2017:

does the block senser have an impact in the runing of the engine if its not connected?

Mr Fixer on April 24, 2017:

Yes there is a fan control module sensor in vw golf make 3, 4 & 5 too that senses when the coolant is hoter and needed cooling, and will automatically toggle from low radiator fan spin to medium or high depending on the current temperature of the coolant present in the radiator.. This sensor is mounted right at top conner driver side of the radiator. And if it goes bad will stop the the radiator.

It has the tendency of kick starting the radiator fan and shutting it down based on instructions from the ECU.

It also has the tendency of kick starting your radiator fan even when your engine has shut down for a while due to incomplete cooling cycle required for the health of your engine.

ABBA BONYO on January 08, 2017:

Keep it up,and all this said here are true.

Irfan (author) from Adelaide, Australia on October 24, 2016:

@zibusiso : I have not heard of a module sensor before. There is a temperature sensor attached to the body near the hose coming from the radiator and some cars (like honda civic) have a second temperature sensor on the radiator. There is a thermostat valve which allows the colder water to flow into the engine but no module sensor.

zibusiso on October 24, 2016:

is there something called a module sensor for VW Golf 4 meant to cool down the car in cases where it is overheating.

Md.Akram Hossain on October 16, 2016:

No doubt that, it's a very intellectual explanation. I am highly pleased to the better analysis of automotive sensing components. hoping that I will get latest information in future also. Have a good days. Allah hafej.

Best regards.


Irfan (author) from Adelaide, Australia on August 03, 2016:

@abu hasssan : thanks for stopping by... :)

@jethro : thank you... :)

Irfan (author) from Adelaide, Australia on August 03, 2016:

hi Abinash

Newer cars a motor fixed with the throttle body. An additional sensor is placed under the accelerator pedal known as the accelerator pedal position sensor which controls the throttle body motor.

Nothing happens if you only have a MAF ... if you don't have a MAF you will have a separate MAP and Air Temperature sensor to get those readings. The TPS value will come from either the TPS sensor or the Accelerator sensor.

At the end of the day these values are required by the ECU therefore it will have to be given one way or the other so that further calculations can be made on how much fuel to deliver in the injectors etc.

abu hasssan on August 03, 2016:

thank you

Abinash on July 13, 2016:

Do all cars have a TPS as well as a MAF sensor. So what happens if my car only has a MAF sensor?

jethro on June 08, 2016:

nice forun

Irfan (author) from Adelaide, Australia on November 02, 2015:

@Raj: search for "OBD II" or OBD 2 scanners. (OBD= onboard diagnostics.)

Raj on November 02, 2015:

Sorry I didn't ask the question clearly. Is it possible to get readings from ECM? For ex, coolant temperature, intake air temperature, ambient temperature, engine temperature, engine rpm etc... If yes, what kind of devices can be attached to get the readings from ECM?

Raj on November 02, 2015:

I wanted to know that is it possibld to get reading from ECM?

Irfan (author) from Adelaide, Australia on November 02, 2015:

@Bresmen : Check for air leaks.

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