Dec 122016

2012 Toyota PriusI have a 2012 Toyota Prius V. As I am traveling along my engine accelerates or engine revs. The only way for me to stop this is to step on the gas pedal.


I consider this as a severe safety issue. Sounds like your accelerator is sticking. This may be from a faulty accelerator pedal sensor. Testing will require a capable scan tool. You may need to take this to a Toyota dealer because not every local shop will have one for a Prius.

Accelerator Pedal Sensor On-Vehicle Inspection


(a) Connect the Techstream to the DLC3.

(b) Turn the power switch on (IG).

(c) Turn the Techstream on.

(d) Enter the following menus: Powertrain / Hybrid Control / Data List / Accel Pedal Pos #1, Accel Pedal Pos #2.

(e) Read the Data List.


Tester Display

Accelerator Pedal Condition

Specified Condition

Accel Pedal Pos #1

Not depressed

(8 to 28%) 0.4 to 1.4 V

Fully depressed

(62 to 92%) 3.1 to 4.6 V

Not depressed → Fully depressed → Not depressed (Accelerator pedal should be operated slowly)

Value changes progressively as shown in the illustration

Accel Pedal Pos #2

Not depressed

(20 to 44%) 1.0 to 2.2 V

Fully depressed

(78 to 100%) 3.9 to 5.0 V

Not depressed → Fully depressed → Not depressed (Accelerator pedal should be operated slowly)

Value changes progressively as shown in the illustration

Remove Accelerator Pedal Assembly

accelerator pedal sensor
(a) Disconnect the accelerator pedal assembly connector.
(b) Remove the 2 bolts and accelerator pedal assembly.

  One Response to “Accelerator Pedal Sensor 2012 Toyota Prius V”

  1. Mine does that too…you are driving down the hwy and the eng revs higher than your speed of travel. I thought it was the CVT slipping. Found out this is how the hybrid system works and nothing to be concerned about. Here is a detailed ans in a Prius forum for more details… To increase the power of the ICE, would require making the ICE physically bigger and heavier. Thus its nominal output for cruising would consume more fuel. Most of the time we don’t need peak power, and usually peak power is only needed for a short time. Thus instead of having an ICE capable of peak power that we don’t need 80% of the time, thus wasting fuel unnecessarily, an electric motor and battery supplements the needed increased power. Of course that can’t be sustained.
    Also the power to RPM curve of an ICE at various loads is not linear. The sweet spot is in the middle. The motor(s) and battery provide the ability to keep the ICE at its sweet spot as much as possible. If the battery SOC is depleated, then of course it can’t supplement the ICE power, so ICE power will have to rise to provide as much demand as it can. What’s interesting though is that because of the PSD configuration, ICE is not restricted to any particular RPM simply because of the vehicle speed. So, ICE can run at a higher RPM, but send some of that to the generator (MG1), which then feeds MG2 to help turn the wheels.

    As for knowing what power is coming or going to what, the only unknown is ICE power, though it can be closely estimated. The HV ECU controls the gating of the individual transistors used in each phase of each of the motors, so it knows how much current and voltage is being delivered or received from the motors. In other words, the HV ECU micro-manages the inverter circuits. On top of that, there are current and voltage sensors to verify power input/output. If the HV ECU guesses wrong about the ICE power output, then either the generator output of MG1 (usually) will be different than expected, or vehicle speed will change more than expected. Excess electrical power will always go to the battery, and if sustained, then the battery SOC will go up. HV will see this and trottle down the ICE, and start using battery power more until SOC returns to nominal, and then HV will equalize things based on this new information.

    If you have the miniscanner, you can pull all the electrical info you want and observe the drivetrain’s behavior.

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