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Symptoms of a Bad Camshaft Position Sensor

Updated on June 24, 2017
Dan Ferrell profile image

Dan Ferrell writes about do-it-yourself car maintenance and repair. He has certifications in automation and control technology.

Problems That Can Be Caused by a Failing Camshaft Position Sensor

A failing camshaft position sensor (CMP sensor) can produce a confusing range of problems, depending on the way it fails and the model of the car:

  • On some vehicles, a failing camshaft sensor may lock the transmission in a single gear until you turn off and restart the engine. This cycle may repeat intermittently.
  • If the sensor begins to fail while your car is moving, you may feel the car jerking while losing power.
  • You may experience a noticeable loss of engine power. For example, the engine can't accelerate above 35mph.
  • The engine may stall intermittently.
  • You may notice poor engine performance including irregular acceleration, misfiring, hard starting, or surging.
  • On some car models, a failed CMP sensor will prevent the ignition from making a spark, so that the engine won't start at all.

Camshaft position sensor
Camshaft position sensor | Source

A Camshaft Position Sensor Can Fail Without Warning

An intermittent or complete CMP sensor failure while on the road could be dangerous. It could happen at any time: You are driving on the highway, moving along in fast traffic, when your engine suddenly loses power. There is nothing to do but watch in horror as a vehicle approaching at 70 miles an hour rear-ends you. Not a pretty picture, but it's happened many times.

Other times the driver becomes aware of a failed CMP sensor when the engine refuses to start.

Here, we'll explore the symptoms of a bad camshaft position sensor and what you can do about it. But let's discuss first what the sensor does.

What Is a Camshaft Position Sensor?

The camshaft controls the opening and closing of the intake and exhaust valves.
The camshaft controls the opening and closing of the intake and exhaust valves. | Source

Your engine's cylinder head houses one or two camshafts—a shaft equipped with offset lobes—to operate the intake and exhaust valves. The crankshaft, located in the engine block, drives the camshaft using gears, a timing chain, or a timing belt.

Camshaft
Camshaft | Source

To determine which cylinder is in its power stroke, your car's computer monitors the rotating position of the camshaft relative to the crankshaft position using a camshaft position (CMP) sensor. It uses this information to adjust the spark timing and the operation of the fuel injectors. Thus, the CMP sensor affects fuel economy, emissions control, and engine efficiency.

Camshaft position sensor (Hall-effect type)
Camshaft position sensor (Hall-effect type) | Source

The two most common camshaft sensors you'll see are the magnetic and Hall-effect types. Both transmit a voltage signal to an electronic control module or to the car's computer.

The magnetic type produces its own AC (alternate current) signal (a sine wave), and you can identify it by its two wires. The Hall-effect type uses an external power source to produce a digital signal (a "square wave," on-or-off) and has three wires.

Note: If you are new to all this, you should know that the camshaft position sensor is a different part from the crankshaft position sensor.

How the Sensor Can Fail

Just like every part or component in your car, the CMP sensor will eventually stop working when it's reached the end of its service life, because an internal part, wire, or related component has failed. The symptoms your engine may experience at this point can vary, depending on the type of sensor failure: for example, a problem in the circuit, the connector, the sensor itself, or a related component.

Once your car's computer detects a CMP sensor failure, it will trigger the engine light and store a diagnostic trouble code (DTC) in its memory (see the table below for common camshaft position sensor trouble diagnostic codes).

CMP Codes and What They Mean

Common CMP Trouble Codes
Source of Trouble
P0340 CMP
Circuit malfunction
P0341 CMP
Circuit range or performance problem
P0342 CMP
Circuit low input
P0343 CMP
Circuit high input
P0344 CMP
Circuit intermittent

Camshaft Position Sensor Location

Source

As you may expect, the specific location of the camshaft position sensor varies by a vehicle's make and model. On most models you can find the sensor somewhere around the cylinder head. Look around the top section of the timing belt/chain cover (in the front of the engine) or at the rear end of the cylinder head. Some GM models may have a special compartment for the sensor.

Also, some Mercury Villager and Nissan Quest models locate the CMP sensor inside the distributor housing, as well as some Dodge Ram B1500, B2500, and B3500 series models with gasoline engines.

Depending on the specific model of your car, your engine may have one or more cam sensors.

If you need help finding the sensor(s), check the vehicle service manual for your particular model. You may find a copy in the reference section of your local public library. I highly recommend that you buy an aftermarket repair manual for your specific vehicle make and model (Haynes is a good inexpensive brand) for reference when doing maintenance and small repairs.

CMP Sensor Troubleshooting

If your car computer has already triggered the engine light, you may retrieve the code (the DTC) using a code reader or a relatively inexpensive scan tool. If you don't own a code reader and can't afford to buy one, and you still can drive your car safely, just go to a nearby auto parts store that retrieves DTCs for free.

After confirming a CMP-sensor related trouble code, it's worth doing some simple tests. A trouble code pointing to a potential CMP sensor failure doesn't necessarily mean that the sensor itself is bad. You may be dealing with a wire, connector, or related component failure that you can fix yourself.

However, confirming the good or bad operation of a camshaft sensor may require a scope. A failing sensor signal, for example, may be hard to check without special equipment. Still, you can do some simple checks in your garage using a digital multimeter (DMM) tool.

  • First, check the condition of the sensor's electrical connector and wires. Unplug the connector and check for rust or contamination, like oil, that is interfering with good electrical contact. Then check for wire damage: broken wires, loose wires, and signs of burns caused by nearby hot surfaces. Also, make sure the sensor wires are not touching spark plug wires or ignition coils, which may interfere with the sensor's signal.
  • After these checks, use a digital multimeter that can test either alternate current (AC) voltage or direct current (DC) voltage, depending on your particular type of camshaft position sensor. You'll also need the correct electrical values for your particular type of sensor. You may find this information in your vehicle repair manual.
  • With some sensors, you may back-probe the wires through the sensor electrical connector.
  • If this isn't possible, see if you can unplug the sensor connector and attach a strand of copper wire to each terminal on the connector. Then plug the connector back in so that the two strands stick out through the connector's housing.
  • Another testing solution is to pierce through each wire using a pin, being careful not to short out the wires during your tests. If you use this last method, use electrical tape to cover the pin holes on the wires' insulation after you're done with your tests to prevent corrosion from creeping into the wires.

Testing a Two-Wire Sensor:

  • If you have a two-wire, magnetic-type CMP sensor, set your multimeter to "AC volts."
  • Have an assistant turn the ignition key on without starting the engine.
  • Check for the presence of power flowing through the circuit. Touch one of your probes to ground (any metal part on the engine) and the other probe to each one of the sensor wires. If neither wire has current, there's a failure in the sensor's circuit.
  • Have your assistant crank or start the engine.
  • Touch one of your meter probes to either one of the sensor wires and the other probe to the other wire. Check your meter display and compare your reading to your manual specifications. In most cases, you'll see a fluctuating signal between 0.3 volts and 1 volt.
  • If there's no signal, you have a bad CMP sensor.

Testing a Three-Wire Sensor:

  • Once you identify the power, ground, and signal wires using your vehicle repair manual, test the sensor's circuit by setting your multimeter to "DC volts."
  • Have an assistant turn the ignition key on, but don't start the engine.
  • Touch the black probe on your meter to ground (a metal bracket, bolt, or metal surface on the engine itself) and the other probe to the power wire. Compare your reading to the specification in your manual.
  • Have your assistant crank or start the engine.
  • Touch the signal wire with the red probe from your meter and the ground wire with the black probe. Compare your reading to the specification in your vehicle repair manual. If the voltage signal is lower than the specification, or no signal comes out of the sensor, most likely the sensor is bad.
  • Remove the sensor and inspect it for signs of physical damage or contamination.

Check the video below to see how you can perform these tests using a test light and a multimeter. It'll give you an idea of the nature of the tests too. If you can't find anything wrong with the sensor or its circuit, it's possible you may have an intermittent failure or a failure in a related component. For example, you may have a weakened or overstretched timing belt or timing belt tensioner. A worn-out belt can prevent the camshaft and crankshaft from synchronizing, causing the CMP sensor to send the wrong signal.

Testing a Camshaft Position Sensor

Sensor Replacement and Cost

If you've confirmed that the camshaft position sensor is bad, you may want to replace it yourself. On some vehicle models, replacing the sensor is just as easy as unplugging the electrical connector, unscrewing the mounting bolt, pulling the sensor out, and installing a new one. On other models you may need to remove one or more components to gain access to the sensor (as you will see in the next video).

Check your car's repair manual for instructions on how to replace the sensor on your particular vehicle model.

Expect to spend anywhere between $30 and $100 (or more) for the sensor itself, depending on your vehicle model. If you take your vehicle to a car shop, you may be looking at $100 or more in labor expenses too.

Replacing a Camshaft Sensor (Nissan Altima)

The symptoms I discussed above are not clear signs that your CMP sensor is bad. Still, if you recognize one or more of these symptoms, try to diagnose the problem as soon as possible. The last thing you want is to get stuck in the middle of the road. Start by getting the trouble codes from your computer memory, and, if necessary, testing the sensor with the help of your vehicle service manual. Sometimes you can determine the cause of the problem and fix it yourself without spending too much time and money.

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    • Dan Ferrell profile image
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      Dan Ferrell 2 days ago

      Hi Phil,

      You seem to have a pre-ignition problem - something is causing the air-fuel mixture to ignite before it should. Usually this points to bad ignition timing, but because of the previous lean condition (vacuum leak), I'm wondering if there's too much carbon build up in the chambers. Also, was there an overheating problem before?

      * Check the ignition timing to make sure it is still good (not too advanced).

      * Check the usual ignition suspects - spark plugs and wires + injectors, (injection system) for carbon deposit source.

      * Also, make sure you're still using the recommended fuel for your model.

      I'm guessing the cam "fault" was intermittent and it triggered the DTCs on and off - hence the 133 faults (?).

      Good luck

    • profile image

      Phil 2 days ago

      Hello Dan

      Had my 96 BMW 318ti on a computer today it showed up 133 repeated faults on the cam sensor. I went out and bought a new one which turned out to be a dud and the car wouldn't run at all. Whilst I had the plenum chamber off (need this off to get to the sensor's plug unfortunately!) I noticed a split in the end of a pipe from the air intake pipe to the injectors. Luck would have it it was at the end of the pipe so trimmed it back to good rubber and refitted it. I refitted the old cam sensor to get back to the spares shop to exchange the sensor which they didn't have any more of (just my luck!). Strangely the symptoms I was experiencing have disappeared so I am taking a guess that the vacuum pipe was causing them. That's good BUT i have noticed a pinking sound under load AND there is the question of the 133 faults? I am debating wether or not I do have a faulty sensor what's your thoughts and if not what else could cause the pinking sound on a modern engine?

      Thanks Dan

    • Dan Ferrell profile image
      Author

      Dan Ferrell 2 days ago

      Hi Jeff,

      Yes, it could be any of those things. Have you check for DTCs (trouble codes)? Start there. Usually a bad crankshaft or camshaft will trigger the check engine light. If the injectors, fuel pump or another system device isn't working properly, the engine might not start.

      Good luck

    • profile image

      Jeff. 3 days ago

      Hi dan.

      I can't start my freelander 2 2.2 td4 2007.

      Cranks over but won't start. Changed the battery and the diesel fuel filter bled it all no air in system.

      Been told it could be the crankshaft / camshaft sensor / fuel pump.

    • Dan Ferrell profile image
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      Dan Ferrell 8 days ago

      Hi Sharon,

      Did you erase the original trouble code after replacing the cam sensor? Otherwise it's going to stay in memory.

      Also, check the connections for contamination, dirt, oil, etc.

      If you have a digital multimeter, you may want to check for incoming voltage and the signal. Your vehicle repair manual may give you the steps for this. You can get an inexpensive, aftermarket manual for your model through Amazon or your local auto parts store.

      Good luck

    • Dan Ferrell profile image
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      Dan Ferrell 2 weeks ago

      Hi Augie,

      How do you know it is damaging the sensor? - Usually oil leaks around the sensor will ruin it. Make sure there are no leaks around.

      Also, a failure of the timing belt, mass air flow sensor, and crankshaft position sensor can trick the computer into "detecting" a fault in the camshaft sensor.

      Hope this helps, good luck

    • Dan Ferrell profile image
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      Dan Ferrell 2 weeks ago

      Hi Terra

      You may need to clean up the trouble codes in the computer memory. If you disconnected the battery while replacing the sensor without using a memory saver, it might take a few weeks for the computer to relearn the best driving strategy for the engine.

      Good luck

    • Dan Ferrell profile image
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      Dan Ferrell 4 weeks ago

      Hi Terra,

      You may need to erase the sensor TC from your computer memory. You can do this with a scanner.

      Also, if you disconnected the battery without using a memory saver while replacing the sensor, your computer may have lost the adaptive learning strategy. It may take some time of driving (miles) before it relearns the best engine operating conditions for your vehicle.

      Good luck.

    • profile image

      Terra 4 weeks ago

      I replaced my camshaft sencor but it still show up on car computer and my car still doesnt run right. What else can I try.

    • profile image

      Augie C 4 weeks ago

      Hi I have changed my Camshaft Sensor A Ciscuit Bank 2 3 times in one week works for 2 days and damages the sensor. I got it at Pep Boys not sure if something else is causing this to fail all the time. Will have to buy the Original one form Nissan

    • Dan Ferrell profile image
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      Dan Ferrell 4 weeks ago

      Hi Pete,

      Your first step is to scan your computer for trouble codes. If there's a problem with the cam sensor, most likely the computer got a code. Probably your local auto parts store will retrieve the codes for you.

      If there's a sensor for it, try to troubleshoot the sensor. My guess is that the repair manual for your make and model will have the procedure.

      Get an aftermarket repair manual, they're inexpensive and very useful.

      Good luck

    • profile image

      tomonator 5 weeks ago

      Hi Chaps .. any advice is fantastic of you :)

      I have a vaux astra 1.7 deisel estate 2003

      I have been told my symptoms relate to the cam shaft sensor .

      it will start no problem but cuts out after about 10 seconds ..turn it off then same again .. as if its stalling ... everything mechanical seems fine .. but im eager to learn something and sort it myself if possible

      thanks Pete

    • profile image

      Dunnie 5 weeks ago

      Thanks Dan.

      I will try what you have advised above. The stater motor seems to be working fine because it always cranks with the same sound even when the car is unable to start. Whenever i experience this hard start, the sound of the exhaust will sound like a lazy sound, not active like the normal one. It always sound like I am using a big pipe straw to blow air instead of the small normal one. During the cranking the engine will sound like its about to ignite and eventually dies just after. I will give feedback after .

    • Dan Ferrell profile image
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      Dan Ferrell 5 weeks ago

      Hi Dunnie,

      Hot related issues sometimes are hard to diagnose.

      Try some of this test/troubleshoot tasks.

      Next time the engine is hard to start open the hood and let the engine 'breathe' for a few minutes and try starting the engine. If it does, you might have issues with the starter motor.

      (just by curiosity, did your mechanic check for gas vapor lock?)

      Also, test the air temperature and cooling sensors.

      Good luck

    • profile image

      Dunnie 6 weeks ago

      Hi guys. I am driving a VW polo Comfortline 2012. I have been experiencing hard start since last year in September especial during hot weather conditions. In the morning where temperature is cool the car starts quite well, but if i leave the car until 11:00 or 12:00 without starting it the car wont start until late in a day after the sun has set. I usual do kick start whenever i experience this, I took it for service to VW but they said everything is completely fine, noting they could find using the scanner(Comp). Sometimes it goes like this, if I drive for say 20 kilos and park at a parking slot which is exposed to the sun for 30 minutes, the car wont start. I have to push it or wait until it cools down completely. I am not sure what could be the problem while the VW dealer could not spot anything.

      Thanks for your assistance in advance.

    • Dan Ferrell profile image
      Author

      Dan Ferrell 6 weeks ago

      Hi preston,

      On some models the computer won't let you drive. Other models you'll experience hard starting issues but you'll be able to drive. Still, you may experience stalling - this makes it unsafe. The engine may stall in the middle of the road. Safer to replace it ASAP.

      Good luck

    • profile image

      preston 6 weeks ago

      can operating without the sensor damage your engine? 2002 gmc envoy

    • Dan Ferrell profile image
      Author

      Dan Ferrell 7 weeks ago

      Hi Robin

      On some models the computer will lock the engine if a overheat condition exists. A failed temp sensor may cause this. This is to save the engine from catastrophic failure.

      Also, did you check/replace the CPS.

      Good luck.

    • Dan Ferrell profile image
      Author

      Dan Ferrell 7 weeks ago

      Hi, Michele,

      If you disconnected power (battery) to replace the sensor, it might give you some trouble. Make sure to erase the trouble code for the cam sensor. It probably gonna take a while for the computer to relearn the best driveability strategy for your model. Also, make sure you didn't unplug a vacuum hose or connector by mistake.

      Good luck

    • profile image

      Michele 8 weeks ago

      I have a 2010 Audi A4 the service engine light came on about a month ago the code reader said the camshaft sensor was bad but the car seemed fine two days ago the car didn't start in the first try then did I pulled out and the car wouldn't go I hit the gas hard and it went then stalled the. Ad started back up but wouldn't go the service engine came up again and the code reader said the camshaft sensor we replaced it but now the car won't start. We also replace the crankshaft sensor a few months ago. Please someone help

    • profile image

      Robin 8 weeks ago

      I have a 96 chevy 3500 with 454 engine. I had a dtc for the camshaft position sensor. One day the truck wouldn't start. It would crank but not start. Had no communication with ecm. A new ignition switch was installed and it started. Drove 15 min trying to get home and the truck lost power then died. After I came to complete stop I tried restarting and engine locked up. Temp gauge instantly shot to max hot when lost power. Was engine lock up caused from sensor?

    • Dan Ferrell profile image
      Author

      Dan Ferrell 2 months ago

      Hi Darcy,

      Check the EGR valve, it my be stuck closed. Other possibilitiy is a fuel pump or ignnition coil starting to fail. They will usually run good when cool until they reach temperature.

      Gool luck.

    • Dan Ferrell profile image
      Author

      Dan Ferrell 3 months ago

      Hi Ron

      You may need to clean the computer's memory (you can do this with a scan tool), or there might be more trouble codes in it.

      Good luck

    • Dan Ferrell profile image
      Author

      Dan Ferrell 3 months ago

      Hi,

      Have you scanned the computer memory for trouble codes? Make sure the sensor is your problem and try to troubleshoot it. The vehicle repair manual for your make and model will help you.

      Good luck

    • Dan Ferrell profile image
      Author

      Dan Ferrell 3 months ago

      Hi Adrian,

      probably this link will help you locate the sensor

      http://www.justanswer.com/chevy/2jdyr-cam-sensor-l...

      Good luck

    • profile image

      Help Dan 3 months ago

      I changed timing chain and both gears. I figured it jumped timing. Im new to cam shaft position sensor. Please help.

      Thanks.

    • profile image

      Adrian 3 months ago

      Hi , I have a 2000 Chevy Silverado 1500 4.8 and I cant find the cam shaft position sensor. I was driving and truck just thumped and turned off. Now wont start and misfires. Can someone tell me location of cam shaft position sensor ?

    • Dan Ferrell profile image
      Author

      Dan Ferrell 3 months ago

      Hi HM,

      Yes, you might want to check the alternator. Your repair manual should give you a few simple tests you can do on your own.

      Good luck

    • profile image

      Haziq M 3 months ago

      Hi Dan, thanks for the feedback. Checked the battery. Its shows around 12v. Even I revved up to 3000rpm. Maybe the alternator already weak. Correct me if im wrong. Thanks.

    • Dan Ferrell profile image
      Author

      Dan Ferrell 3 months ago

      Hi HM,

      The DTC may be pointing to a circuit malfunction.

      Make sure you have a good, charged battery and no problems with the starting system (connections and starter motor)

      Check the sensor circuit -- harness (opens or shorts), poor electrical connection.

      Good luck

    • profile image

      Haziq M 4 months ago

      Hi. What if the DTC tells Camshaft signal incorrect/not recognize.

      Merc E230 W210

      Thanks.

    • Dan Ferrell profile image
      Author

      Dan Ferrell 4 months ago

      Hi Pat,

      Apparently you have a fault in the circuit, check the wires that connect to the sensor for cuts or damage. If you feel comfortable using a digital multimeter, test for ground, power and signal voltage to the sensor. The problems seems to be more likely in the circuit. But don't discard a faulty sensor.

      Testing will be easier if you have the repair manual for your car make and model. You can find relatively inexpensive aftermarket manuals at Amazon and your local auto parts store.

      Good luck.

    • profile image

      Pat Taillon 4 months ago

      2003 Cadillac cts. Turned the key and vehicle to seconds after releasing key to start. Approx 3 simular starts within an hour the check engine light came on. Took to auto store for diagnosis code P0343 showed up. Camshaft position sensor A Circuit high input B1 reading. Hoping for opinion on sensor or cause that would trigger sensor. Thanks in advance. Pat

    • profile image

      adnan 5 months ago

      thanks

    • Dan Ferrell profile image
      Author

      Dan Ferrell 6 months ago

      Hi Patricia,

      Can be just coincidence, but your mechanic should be able to test the sensors to make sure they are working correctly before replacing them. Maybe something got disconnected during the service procedure that trigger the engine light.

      Good luck.

    • profile image

      patricia 6 months ago

      having issues with my car passing emissions it is saying cam shaft sensor out of timing and also speed senor just replaced valve cover and new plugs this didn't arise until we done this

    • Dan Ferrell profile image
      Author

      Dan Ferrell 7 months ago

      Hi nyasha

      Have you checked for a spark leak? Also, check the boot and the spark plug to see in which condition they are. Make sure four cylinder wire is receiving the command from the computer to fire.

      Good luck

    • profile image

      nyasha_nyabango@yahoo.com 7 months ago

      hi i am working on a toyota 3rz engine , cylinder no 4 is not contributing any power to the engine what can cause that. all valves are closing the compression is ok . the ht lead is supplying the spark . but when i pull out the ht leadf it shows there is no contribution

    • Dan Ferrell profile image
      Author

      Dan Ferrell 8 months ago

      Hi Dam

      Yes, the CMP sends a pulse signal to the computer when cylinder 1 is about to reach TDC on the compression. This is to synchronize and sequence the injectors.

      Have you check for any computer trouble codes? If you get a code for the CMP, first check it to make sure the sensor is the one causing trouble, then check the circuit (connectors and wires) betwen the sensor and the computer.

      Good luck.

    • profile image

      Dam 8 months ago

      On a 98 ford explore V6 does the camshaft positioning sensor control The fuel injectors? I'm getting fuel when I turn the key on when I crank the motor fuel pump is not pumping in my Fuel injectors aer not pulsing?

    • profile image

      Fahad 8 months ago

      HI, i have been looking for the soulutin for my Audi TT 1.8 coupe 2003 A/T..

      i bought this car whit engine light ON, i did scan and the code i forgot, cause it was long time ago and car was still running.. i cleared the code and it cam back after next start.. later on it becomes difficult to start the car sometimes, after 2,3 cranks it get starts... i kept it driving this way.. i remember it went off once while driving.. but usually i had trouble to start the car in one self... i parked this car for few months.. batter went dead and car didnt started again.. i changed the battery still its cranking but not starting up... anybody has any idea??

      i am about to replace camshaft position sensor and crank sensor soon because on youtube and other sites recommends things like this happen if one of these sensors are not working..

      by the way i did the scan again last week it was code P017 something i cleared the code but because i cant start the car i dont know what was the code for...i cant see any code unless the car starts again..its on but no error until it gets starts..(my bad)

      what are your suggestions??

      Thanks

    • Dan Ferrell profile image
      Author

      Dan Ferrell 8 months ago

      Hi Grizzly,

      There could be seeral reasons for a lean code, if you're not getting a specific circuit malfunction DTC from the computer, check for a possible vacuum leak, dirty MAF sensor, and also check the air filter housing and assembly for a leak after the MAF sensor (unmetered air).

      When was the last time you changed the fuel filter (every year or two is the most recommended) a clogging filter can give you this type of problem.

      (Sorry for the late response, your comment was wrongly caught by the spam detector"

      Good luck

    • Dan Ferrell profile image
      Author

      Dan Ferrell 8 months ago

      Hi Dilly,

      Sometimes when a pump is on the way out, it'll cut out after a few minutes of driving. And the same thing happens some times with the ignition control module. Let them cool down and they'll come back to life. It can drive you crazy. But after some time, they'll just die.

      (Sorry for the late response - the comment was wrongly cut by the spam detection robot)

      Good luck

    • Dan Ferrell profile image
      Author

      Dan Ferrell 8 months ago

      Hi Kelly,

      When your car computer stores a DTC (diagnostic trouble code), it only points to the circuit where it detected a poetntial malfunction. In this case, the camshaft sensor circuit. It doesn't necessarily meand the sensor itself is bad. You still need to verify whether the sensor is bad, or the circuit that makes the sensor work. You need to troubleshoot the circuit and the sensor to see where the fault is located.

      If the gas cap is not closing tight, yes, it could trigger the check engine light. You might want to replace the cap with a new one and then check to see if the light goes on. Otherwise, have the sensor and circuit checked.

      Good luck.

    • profile image

      KellyT 8 months ago

      Hello, I replaced my Camshaft Sensor as my engine light came on and the code said it was the sensor. However, after driving it for a few days, the engine light came back on... Camshaft sensor again. What could cause this? Also, my gas cap doesn't click anymore... could this also cause my engine light to come on??? Thanks in advance for any help!

    • Dan Ferrell profile image
      Author

      Dan Ferrell 8 months ago

      Hi Thomas,

      Yes, usually on electronic components try to buy brand quality replacement or OEM. You'll save yourself from a lot of trouble, even if you spend a little more.

      Glad to hear the car is back on the road.

      Good luck.

    • profile image

      Thomas Falater 8 months ago

      This happened to my Mercedes and I checked the wires, did all the tests, and replaced my camshaft position sensor with a $30 one. Two days later the check engine light came on with the same error message 'camshaft position sensor', although the engine ran fine. I bought a Bosch brand position sensor for $100 and installed that and it solved the problem. The check engine light stayed off. Don't buy the cheap sensors. Thomas Falater

    • profile image

      Grizzly 9 months ago

      Would a starting to fail sensor cause lean codes when stalling. Have checked all other causes of lean code but nothin. Could this be the problem with Ford engine stall problem with lean codes that no one can figure out.

    • Dan Ferrell profile image
      Author

      Dan Ferrell 9 months ago

      Hi James,

      The procedure is not that complicated, but you may want to check the repair manual for your make and model. You can find inexpensive manuals in amazon. The investment will pay for itself after your first maintenance/repair like replacing the CPS.

      https://www.amazon.com/Haynes-Repair-Manual-1995-B...

      Good luck.

    • profile image

      James Lang 9 months ago

      I have a 1999 chev. Blazer and my CAMSHAFT POSITION SENSOR is located in the Distributor cap! I seen videos of people just changing them, but some people say that it should be relearn first! Can you give me some insight?

    • Dan Ferrell profile image
      Author

      Dan Ferrell 10 months ago

      Hi Chris,

      Did you check fuel pressure and volume? Compare your figures to specs for your specific model- you can find them in your repair manual.

      This other article might be of help too:

      https://axleaddict.com/auto-repair/bad_starter_sym...

      Good luck.

    • profile image

      Chris Hammac 10 months ago

      I have a 2003 Ford Escape XLT with a crank/no start condition. I've checked fuel, spark and compression. All are present. I installed a new crankshaft position sensor but I noticed that when I turn the motor over, it only shows rotation on the tachometer occasionally. That seems to be when the motor actually sounds like it wants to start. What could be causing the intermittent rotation issue? Is there something else I should be looking at?

    • Dan Ferrell profile image
      Author

      Dan Ferrell 10 months ago

      Hi Chrystal

      That depends on the repair (labor) plus what parts they're going to replace. You can check at RepairPal.

      Good luck.

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      Chrystal Slonecker 10 months ago

      I have my 2004 quest at shop. They just to told me the problem with it, is this- $515.00 to fix..is that reasonable?

    • Dan Ferrell profile image
      Author

      Dan Ferrell 10 months ago

      Hi Charles,

      It seems from what you describe that your ignition switch might be bad, need to check it first; also check the starting circuit for a bad connection (including the battery -have it checked at an auto parts store, minimum).

      Good luck

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      Charles1990 10 months ago

      I have an 99 Tahoe and I turned the key the truck won't turn on at all I have power and fuel what do you think it might be plus wen I turned key radio turns off. Not my head lights

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      Dilly 11 months ago

      I have a 2006 dodge charger and after so many miles of riding my car will just cut off in mid drive as if it's out of gas... I have to let it sit for about 30mins then it will crank back up... Someone told me that it sounds like the fuel pump is getting to hot... I don't know.... What do you think?

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      Andy 11 months ago

      DIAGNOSTIC CODE CHEAT

      On the 2001-2007 Dodge Caravans and Chrysler Town and Countrys, if you turn the ignition on/off/on/off/on (not actually starting engine) quickly, where the mileage is displayed it will give you the diagnostic code then say done. If there is more than oe code it will give you the codes one at a time and then say done.

      https://www.youtube.com/watch?v=DN14htXm8GU

    • Dan Ferrell profile image
      Author

      Dan Ferrell 12 months ago

      Hi Bud,

      I don't have those values with me either. But the codes could be related if the computer went into limp mode and is operating under a standard value to compensate. So the O2 sensor may be registering out of range. If you can't find the ohm values for your cmp sensors with a little search online, head over to

      http://www.realworldautomotive.com/

      and ask for the CMP values for your application. They are more likely to help you with it.

      Good luck.

    • Dan Ferrell profile image
      Author

      Dan Ferrell 12 months ago

      Hi Sunny,

      You might be right. It sounds like you got a blown head gasket. The white smoke and lack of compression seem to point in that direction. Do a compression test. Hopefully you were able to stop the engine before any major damage occurred.

      Good luck.

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      Sunny 12 months ago

      I have a 97 Mitsubishi marage deluxe (standard)

      I chose to use the freeway which i never use; i always go thru town, but i got up to about 60 in 5th gear, and my car started to overheat my foot was to the floor board trying to keep up to freeway speed and keeping in mind that the pedal was floored; the speedometer kept going down, i was loosing speed in fifth with the pedal to the floor, white smoke started coming thru the vents as i turned the fan on to try and cool it down a little,

      So white smoke was coming from the engine, and also it didnt make any crazy noises either and there wasnt any black smoke so i font think its blown, it turns over but theres hardly any compression from what i could feel when i put my finger in the spark plug hole as my friend turned it over, soo no combustion?

      My friend said a snapped camshaft, at first i thought the engine seized, and then a blown head gasket made more applyable sense because theres water in the oil im pretty sure, i took the plugs out and turned it over to try and flush what ever was in the piston bays out do it would start, assuming it had water/voolant

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      Bud 12 months ago

      Hi, I have a 2011 Subaru Outback w/ a 3.6L (6 cyl) boxer.

      How likely is it to have an OBDll trouble code of p0011 & p0021 plus p0420 which indicates both L&R CMP throwing a failure code. Also the p0420 (catalyst sys. below threshold). Can these codes be related? I have been scratching my head over this. I do have a 2011 Subaru service/ repair manual on CD, I can not find the ohm value for the intake cam sensor. Is there a way to test it's value , or in other words is there a range I should be looking for? BTW my car has all the symptoms you described in your post "Symptoms of a bad camshaft position sensor. Thanks in advance, Bud

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      Cesar 12 months ago

      Hello There,

      -It seems I replaced the CAM sensor with a CRANKSHAFT sensor. Are there any potential problems?

    • Dan Ferrell profile image
      Author

      Dan Ferrell 12 months ago

      Hi Danny,

      Have you scanned the computer for any DTCs? That would be a good start. From what you describe it seems your fuel pump or ignition coil are having some problems, but that's hard to tell without getting some info from the computer. Any of the sensors may be also at fault.

      If there's an auto parts store you can get to and have them scan the computer, get the codes and see what happens.

      Good luck.

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      Danny 12 months ago

      Hi, After driving my car for 30 minutes my car loses power and revs fly high and can just limp along. My cars been out of action for 18 months with this problem. I live in the tropics and unfortunately I cant find a decent mechanic. Does anyone think this could be the crank/camshaft sensors? Please help!

    • Dan Ferrell profile image
      Author

      Dan Ferrell 13 months ago

      Hi Rachel,

      Do you have enough battery power? Also, check the starter solenoid.

      I'd start with these two.

      Good luck

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      Rachel 13 months ago

      2005 terracan won't start. Ticks over but doesn't crank over to start. Need help please!

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      amanda 14 months ago

      Hi I have a 2012 lancer mitsubishi ES an i can't fie the camshaft to replace it can you help me thank u

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      D Moore 2 years ago

      What can you do if the connector itself is bad on the rear cam sensor on a 2004 Nissan Quest?

    • Dan Ferrell profile image
      Author

      Dan Ferrell 2 years ago

      Hi ttrimm, thanks for posting and making the photos available. They were just perfect for the article. And glad to hear you were able to replace both cmp's without any problems.

    • ttrimm profile image

      ttrimm 2 years ago

      Hi. just wanted to say that it's totally awesome that you are using my photos. We had to replace both of them when we did this!

    • Mark Johann profile image

      Mark Johann 2 years ago from Italy

      I am new to this and it will help me install it someday. I did not know about this kind of camshaft sensor before. This is a great help for motorists who are not that expert in automotive to help them determine malfunctions inside an engine.