P1120
P1120 - Accelerator Pedal Position Sensor Circuit MalfunctionCIRCUIT DESCRIPTION
DTC Detection Condition:
Accelerator pedal position sensor is mounted on the throttle body and it has 2 sensors to detect the accelerator position and a malfunction of the accelerator position's own.
The accelerator pedal position sensor is connected with the accelerator pedal by the accelerator wire and the voltage applied to terminals VPA and VPA2 of the ECM changes between 0 V and 5 V in proportion to the opening angle of the accelerator pedal.
The ECM judges the current opening angle of the accelerator pedal by these signals output from terminals VPA and VPA2 and the ECM controls the throttle motor based on these signals.
If this DTC is stored, the ECM cuts the power for the throttle motor and magnetic clutch, and the throttle valve is fully closed by the return spring. However, the opening angle of the throttle valve can be controlled by the accelerator pedal through the throttle cable.
HINT: After confirming DTC P1120, use the OBD II scan tool or TOYOTA hand-held tester to confirm the throttle valve opening percentage.
Wiring Diagram:
INSPECTION PROCEDURE
HINT:
- If DTCs P0110, P0115, P0120, P0450 and P1120 are output simultaneously, E2 (sensor ground) may be open.
- Read freeze frame data using TOYOTA hand-held tester or OBD II scan tool, as 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:
Steps 2 - 4:
TOYOTA hand-held tester
Steps 1 - 2:
Step 3:
OBD II scan tool (excluding TOYOTA hand-held tester)