Torque Diagnostic Display on a Toyota Prius Using an ELM327 Adapter
As a Prius owner, I have learned a lot about how to troubleshoot any issues that might arise. Luckily, I'm willing to share my findings!
What Is Torque?
The application Torque is available in the Android Play Store in both free and paid versions. The paid version is $5 and is well worth the cost. It's compatible with Bluetooth-equipped Android smartphones.
You can use it to connect to a Bluetooth-compatible ELM327 OBDII adapter. An ELM327 adapter simply provides access to the on-board diagnostics (OBD) interface that has been standard on most vehicles since 1996. OBD performs such functions as reading out diagnostic trouble codes (DTCs) and checking the temperature of vehicle fluids, the voltage of oxygen sensors, instantaneous fuel economy, trip fuel economy, and so on. The Bluetooth part is especially important here since it allows you to connect a laptop (using software other than Torque), Android tablet, or smartphone to gain access to diagnostic codes and the information that the vehicle's ECU keeps track of regarding the engine, the transmission and so forth.
Torque will work with the majority of ELM327 adapters available from Amazon or Ebay, and you don't even have to buy a top-of-the-line adapter.
Torque for Android (for Prius)
Screenshot of the home screen of the Torque app for Android
Author (jesimpki)
Using Android Tablet or Phone to Display Info While Driving
Instead of using a phone, you can install Torque on any Bluetooth-capable Android tablet and mount it to the dash. Mine is mounted using Velcro which holds the tablet just fine and can always be removed.
Author (jesimpki)
My Android phone held in a cup holder mount, using one of my dashes on Torque to display various indicators. Only the voltage for the 12-Volt battery is showing as the Prius isn't in READY mode.
Author (jesimpki)
ELM327 OBDII Bluetooth Adapters
Many different brands of ELM327 Bluetooth adapters are available. Better-known brands such as the Kiwi Bluetooth Scanner made by PLX Devices are at the more expensive end of the scale. The cheaper ones are produced under random generic-sounding names and the majority of them look exactly alike. These are technically clones, but that hasn't stopped anyone from buying them, and most Torque users have no trouble using the ones at the cheaper end of the spectrum which can be bought or bid on in the $15-$20 range.
Prius-Specific Information
Even more useful in the case of the Prius, Torque can be used with custom PIDs made available for the Gen 2 Prius (2004-2009 Model Years) or the Gen 3 Prius (Late 2009 to Present Model Years) available for download from PriusChat.com (courtesy of usbseawolf2000). These PIDs let you use Torque to acquire more useful information such as:
- the actual state-of-charge of the high voltage battery pack;
- the voltage of individual groups of batteries (which can be useful in determining the health of high mileage or aging battery packs)'
- and how much you are using regenerative braking rather than friction braking to slow the vehicle down. Regenerative braking charges the battery pack instead of wasting energy turning forward momentum into heat.
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Monitoring Voltage
Screenshot of another dash I have set up just to display the voltages of individual blocks of battery cells in the high-voltage battery pack, along with a few temperature sensors and the speed of the high-voltage cooling fan.
Author (jesimpki)
Where to Connect an ELM327 Adapter in a Prius
It's easy to access, and right in front of you when you're in your Prius; right in front of your right leg, to be exact. Look under the dash below the steering wheel and column, and you'll see a multi-pin female plug that the end of an OBDII adapter will fit right into.
Depending on the size of the adapter you purchased, you might have issues or concerns about bumping it while you are driving. Even though mine is fairly large, I don't have any issue avoiding the adapter when I have it plugged in (which all the time, except when I'm not driving). There are various-sized adapters available, so if this is a concern for you, you can find ones that don't extend out as far as mine.
The location of the OBD II port on a second-generation Prius
Author (jesimpki)
ELM327 OBD II adapter plugged in
Author (jesimpki)
Amount of room between driver's right leg and OBD adapter, accelerator pedal depressed
Author (jesimpki)
What If ABS or Traction-Control Warning Lights Activate While Using Torque?
Occasionally you might notice that after parking on short trips and leaving your tablet or smartphone running Torque, that upon starting up your ABS, VSC, and possibly the traction-control warning lights are on, and braking is mostly being done via the friction brakes. Nothing is actually wrong with your Prius: Torque has simply entered a scanning mode, trying to regain communication with the ECUs in your Prius, and the ECUs didn't take kindly to this, so they detected a problem and went into the default mode of restricting regenerative braking.
If this happens to you:
- Park somewhere safe. Don't try to do this while you are driving or at an intersection; you don't want to risk an accident or impede the flow of traffic!
- Remove the Bluetooth adapter.
- Power your Prius on and off two or three times, until the warning lights turn off after going into READY mode.
You can prevent this ECU miscommunication from occurring by going into your vehicle profile in Torque, scrolling to the bottom, and specifying you want to use a particular CAN-bus communication protocol, specifically the ISO 15765-4 CAN (11-Bit 500k baud) option. This way, when Torque loses connection, it will know to try reconnecting using this protocol.
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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.
