Troubleshooting

DTC P2121 THROTTLE/PEDAL POSITION SENSOR/SWITCH "D" CIRCUIT RANGE/PERFORMANCE

HINT: This is repair procedure for the "accelerator pedal position sensor".

CIRCUIT DESCRIPTION

DTC Detection Condition:

HINT:
- This electrical throttle system does not use a throttle cable.
- This accelerator pedal position sensor is a non-contact type.

The accelerator pedal position sensor is mounted in the accelerator pedal to detect the angle of the accelerator pedal. This sensor is electronically controlled and uses Hall-effect elements. In the accelerator pedal position sensor, the voltage applied to terminals VPA and VPA2 of the ECM changes between 0 V and 5 V in proportion to the angle of the accelerator pedal. The VPA is a signal to indicate the actual accelerator pedal angle and is used for the engine control. VPA2 is used to detect malfunctions of the sensor itself.

The ECM judges the current angle of the accelerator pedal from these signals input from terminals VPA and VPA2, and the ECM controls the throttle motor based on these signals.

MONITOR DESCRIPTION

Monitor Strategy:

Typical Enabling Conditions:

Typical Malfunction Thresholds:

The accelerator pedal position sensor is mounted on the accelerator pedal bracket and consists of two sensors VPA and VPA2. The VPA is used to detect accelerator pedal position, and the VPA2 is used to monitor the VPA and detect faults in the sensor itself. When difference between voltage outputs, of the VPA or VPA2 deviates from the standard range, the ECM concludes that there is a defect in the accelerator pedal position sensor. The ECM turns on the MIL and a DTC is set.

Wiring Diagram:

INSPECTION PROCEDURE

HINT: Read freeze frame data using the hand-held tester or the OBD II scan tool. Freeze frame data records the engine conditions when a malfunction is detected. When troubleshooting, it is useful for determining whether the vehicle was running or stopped, the engine was warmed up or not, the air-fuel ratio was lean or rich, etc. at the time of the malfunction.

Step 1 - 2:

Step 2 (Continued):

Hand-held tester

Step 1:

Step 2:

OBD II scan tool (excluding hand-held tester)