P2121

1ZZ-FE ENGINE CONTROL SYSTEM: SFI SYSTEM: P2121: Throttle / Pedal Position Sensor / Switch "D" Circuit Range / Performance

DTC P2121 - Throttle / Pedal Position Sensor / Switch "D" Circuit Range / Performance

DESCRIPTION

HINT: This DTC relates to the Accelerator Pedal Position (APP) sensor.

Refer to DTC P2120 (P2120).





MONITOR DESCRIPTION

When the difference between the voltage outputs of VPA1 and VPA2 deviates from the standard range, the ECM determines that there is a malfunction in the APP sensor. The ECM then illuminates the MIL and sets the DTC.
If the malfunction has not been repaired successfully, the DTC is set 1 second after the engine is started.

MONITOR STRATEGY





TYPICAL ENABLING CONDITIONS





TYPICAL MALFUNCTION THRESHOLDS





FAIL-SAFE

When any of DTCs P2120, P2121, P2122, P2123, P2125, P2127, P2128 and P2138 are set, the ECM enters fail-safe mode. If either of the 2 sensor circuit malfunctions, the ECM uses the remaining circuit to calculate the accelerator pedal position to allow the vehicle to continue driving. If both of the circuits malfunction, the ECM regards the accelerator pedal as being released. As a result, the throttle valve is closed and the engine idles.
Fail-safe mode continues until a pass condition is detected, and the ignition switch is turned OFF.

WIRING DIAGRAM

Refer to DTC P2120 (P2120).

INSPECTION PROCEDURE

HINT: Read freeze frame data using Techstream. The ECM records vehicle and driving condition information as freeze frame data the moment a DTC is stored. When troubleshooting, freeze frame data can be helpful in determining whether the vehicle was running or stopped, whether the engine was warmed up or not, whether the air-fuel ratio was lean or rich, as well as other data recorded at the time of a malfunction.

PROCEDURE

1. CHECK ANY OTHER DTCS OUTPUT (IN ADDITION TO DTC P2121)
(a) Connect Techstream to the DLC3.
(b) Turn the ignition switch to the ON position.
(c) Turn the tester on.
(d) On the tester, select the following menu items: Powertrain / Engine and ECT / Trouble Codes.
(e) Read DTCs.
Result:





HINT: If any DTCs other than P2121 are output, troubleshoot those DTCs first.

B -- GO TO DTC CHART
A -- Continue to next step.
2. REPLACE ACCELERATOR PEDAL ASSEMBLY
NEXT -- Continue to next step.
3. CHECK WHETHER DTC OUTPUT RECURS (DTC P2121)
(a) Connect Techstream to the DLC3.
(b) Turn the ignition switch to the ON position.
(c) Turn the tester on.
(d) Clear DTCs (DTC Check / Clear).
(e) Allow the engine to idle for a minute.
(f) Rev up the engine several times.
(g) On the tester, select the following menu items: Powertrain / Engine and ECT / Trouble Codes.
(h) Read DTCs.
Result:





B -- CHECK FOR INTERMITTENT PROBLEMS
A -- REPLACE ECM