P2121

3UZ-FE ENGINE CONTROL SYSTEM: SFI SYSTEM: P2121: Throttle / Pedal Position Sensor / Switch "D" Circuit Range / Performance
P2121 - Throttle / Pedal Position Sensor / Switch "D" Circuit Range / Performance

DESCRIPTION

Refer to DTC P2120 P2120.





MONITOR DESCRIPTION

When the difference between voltage outputs of VPA1 or VPA2 deviate from the standard range, the ECM concludes that there is a defect in the accelerator pedal position sensor. The ECM illuminates the MIL and sets the DTC. This monitor runs for 1 second (the first second of engine idle) after the engine is started.

MONITOR STRATEGY





TYPICAL ENABLING CONDITIONS





TYPICAL MALFUNCTION THRESHOLDS





FAIL-SAFE

The accelerator pedal position sensor has 2 (main and sub) sensor circuits. If a malfunction occurs in either of the sensor circuits, the ECM detects the abnormal signal voltage difference between the 2 sensor circuits and changes to fail-safe mode. In fail-safe mode, the functioning circuit is used to calculate the accelerator pedal opening angle to allow the vehicle to continue driving. If both circuits malfunction, the ECM regards the opening angle of the accelerator pedal as being fully closed. In this case, the throttle valve remains closed as if the engine is idling.

If a "pass" condition is detected and the ignition switch is turned OFF, the fail-safe operation stops and the system returns to normal.

CONFIRMATION DRIVING PATTERN





- Connect the Techstream to the DLC3.

- Turn the ignition switch to ON and turn the Techstream ON.

- Clear DTCs (even if no DTCs are stored, perform the clear DTC operation).

- Turn the ignition switch off and wait for at least 30 seconds.

- Turn the ignition switch to ON and turn the Techstream on [A].

- Fully depress and release the accelerator pedal [B].

- Check that 20 seconds or more have elapsed since the ignition switch was turned to ON.

- Enter the following menus: Powertrain / Engine / Trouble Codes [C].

- Read the DTCs.

HINT
- If a DTC is output, the system is malfunctioning.
- If a DTC is not output, perform the following procedure.
- Enter the following menus: Powertrain / Engine / Utility / All Readiness.

- Input the DTC: P2121.

- Check the DTC judgment result.





HINT
- If the judgment result shows ABNORMAL, the system has a malfunction.
- If the judgment result shows INCOMPLETE or UNKNOWN, perform steps [B] through [C] again.
- If no DTC is output, perform a universal trip and check for permanent DTCs Reading and Clearing Diagnostic Trouble Codes.

HINT
- If a permanent DTC is output, the system is malfunctioning.
- If no permanent DTC is output, the system is normal.
WIRING DIAGRAM

Refer to DTC P2120 P2120.

INSEPCTION PROCEDURE

HINT
- Read freeze frame data using the Techstream. Freeze frame data records the engine conditions when malfunctions are detected. When troubleshooting, freeze frame data can help determine if the vehicle was moving or stationary, if the engine was warmed up or not, if the air-fuel ratio was lean or rich, and other data from the time the malfunction occurred.
- This DTC is related to the accelerator pedal position sensor.
PROCEDURE

1. CHECK OTHER DTC OUTPUT

Result:





B -- GO TO DTC CHART Diagnostic Trouble Code Descriptions
A -- Continue to next step.

2. REPLACE ACCELERATOR PEDAL

NEXT -- Continue to next step.

3. CHECK OUTPUT DTC (ACCELERATOR PEDAL POSITION SENSOR DTCS ARE OUTPUT AGAIN)

(a) Clear DTCs Reading and Clearing Diagnostic Trouble Codes.

(b) Refer to the confirmation driving pattern for P2121.

(c) Read the DTCs.

Result:





B -- CHECK FOR INTERMITTENT PROBLEMS

A -- REPLACE ECM Service and Repair