P2121

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

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

CIRCUIT DESCRIPTION

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

DTC Detection Condition:

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. The accelerator pedal position sensor has 2 sensors elements / signal output: VPA and VPA2.

VPA is used to detect the actual accelerator pedal angle (used for engine control) and VPA2 is used to detect malfunction in VPA. When the difference between the voltage outputs of VPA and VPA2 deviates from the standard, the ECM concludes the accelerator pedal position sensor has a malfunction. 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:

Step 2:

Hand-held tester

Step 1 - 2:

OBD II scan tool (excluding hand-held tester)