P2122
2UZ-FE ENGINE CONTROL SYSTEM: SFI SYSTEM: P2120: Throttle / Pedal Position Sensor / Switch "D" Circuit
DTC P2120 - Throttle / Pedal Position Sensor / Switch "D" Circuit
DTC P2122 - Throttle / Pedal Position Sensor / Switch "D" Circuit Low Input
DTC P2123 - Throttle / Pedal Position Sensor / Switch "D" Circuit High Input
DTC P2125 - Throttle / Pedal Position Sensor / Switch "E" Circuit
DTC P2127 - Throttle / Pedal Position Sensor / Switch "E" Circuit Low Input
DTC P2128 - Throttle / Pedal Position Sensor / Switch "E" Circuit High Input
DTC P2138 - Throttle / Pedal Position Sensor / Switch "D" / "E" Voltage Correlation
CAUTION / NOTICE / HINT
HINT: These DTCs relate to the Accelerator Pedal Position (APP) sensor.
DESCRIPTION
HINT:
- This accelerator pedal position sensor is a non - contact type.
- This ETCS (Electronic Throttle Control System) does not use a throttle cable.
The Accelerator Pedal Position (APP) sensor is mounted on the accelerator pedal bracket and has 2 sensor circuits: VPA1 (main) and VPA2 (sub). The voltage, which is applied to terminals VPA1 and VPA2 of the ECM, varies between 0 V and 5 V in proportion to the operating angle of the accelerator pedal (throttle valve). A signal from VPA1 indicates the actual accelerator pedal opening angle (throttle valve opening angle) and is used for engine control. A signal from VPA2 conveys the status of the VPA1 circuit and is used to check the APP sensor itself.
The ECM monitors the actual accelerator pedal opening angle (throttle valve opening angle) through the signals from VPA1 and VPA2, and controls the throttle actuator according to these signals.
HINT: After confirming DTC P2120, P2122, P2123, P2125, P2127, P2128 and P2138, use the Techstream or the OBD II scan tool to confirm the throttle valve opening percentage.
HINT:
- Accelerator pedal positions are expressed as voltages.
- AP stands for Accelerator Pedal.
MONITOR DESCRIPTION
When VPA or VPA2 deviates from the standard, or the difference between the voltage outputs of the two sensors is less than threshold, 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.
Example:
When the voltage output of the VPA is below 0.2 V or exceeds 4.8 V.
MONITOR STRATEGY
TYPICAL ENABLING CONDITIONS
TYPICAL MALFUNCTION THRESHOLDS
P2120:
P2122:
P2123:
P2125:
P2127:
P2128:
P2138:
COMPONENT OPERATING RANGE
FAIL-SAFE
The accelerator pedal position sensor has two (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 two sensor circuits and switches to limp mode. In limp mode, the remaining circuit is used to calculate the accelerator pedal opening to allow the vehicle to continue driving.
If both circuits malfunction, the ECM regards the opening angle of the accelerator pedal to be fully closed. In this case, the throttle valve will remain closed as if the engine is idling.
If a "pass" condition is detected and then the ignition switch is turned OFF, the fail-safe operation will stop and the system will return to normal condition.
WIRING DIAGRAM
INSPECTION PROCEDURE
HINT: Read freeze frame data using the 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. READ VALUE USING TECHSTREAM (ACCELERATOR POSITION)
(a) Connect the Techstream to the DLC3.
(b) Turn the ignition switch ON and turn the tester ON.
(c) Enter the following menus: Powertrain / Engine and ECT / Data List / ETCS / Accelerator Position No. 1 and Accelerator Position No. 2.
(d) Read the values displayed on the tester.
Standard voltage:
OK -- CHECK WHETHER DTC OUTPUT RECURS (ACCELERATOR PEDAL POSITION SENSOR DTCS)
NG -- Continue to next step.
2. CHECK HARNESS AND CONNECTOR (ACCELERATOR PEDAL POSITION SENSOR - ECM)
(a) Disconnect the A20 accelerator pedal position sensor connector.
(b) Disconnect the E9 ECM connector.
(c) Measure the resistance between the wire harness side connectors.
Standard resistance (Check for open):
Standard resistance (Check for short):
(d) Reconnect the ECM connector.
(e) Reconnect the accelerator pedal position sensor connector.
NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR
OK -- Continue to next step.
3. INSPECT ECM (VCPA AND VCP2 VOLTAGE)
(a) Disconnect the A20 APP sensor connector.
(b) Turn the ignition switch ON.
(c) Measure the voltage of the E9 ECM connector.
Standard voltage:
(d) Reconnect the APP sensor connector.
NG -- REPLACE ECM
OK -- Continue to next step.
4. REPLACE ACCELERATOR PEDAL ROD ASSEMBLY
(a) Replace the accelerator pedal rod assembly Removal.
NEXT -- Continue to next step.
5. CHECK WHETHER DTC OUTPUT RECURS (ACCELERATOR PEDAL POSITION SENSOR DTCS)
(a) Connect the Techstream to the DLC3.
(b) Turn the ignition switch ON and turn the tester ON.
(c) Clear the DTCs DTC Check / Clear.
(d) Allow the engine to idle for 15 seconds.
(e) Enter the following menus: Powertrain / Engine and ECT / Trouble Codes.
(f) Read the DTCs.
Result:
B -- SYSTEM OK
A -- REPLACE ECM