P2127

3UZ-FE ENGINE CONTROL SYSTEM: SFI SYSTEM: P2120,P2122,P2123,P2125,P2127,P2128,P2138: Throttle / Pedal Position Sensor / Switch "D" Circuit


DESCRIPTION

A vehicle that is equipped with an Electronic Throttle Control System (ETCS) does not have a throttle cable. The APP sensor is mounted on the accelerator pedal bracket. The APP sensor has 2 sensor elements/signal outputs: VPA1 and VPA2. VPA1 is used to detect the actual accelerator pedal angle (used for engine control) and VPA2 is used to detect malfunctions in VPA1. Voltage applied to VPA1 and VPA2 changes between 0.4 V and 4.8 V in proportion to the accelerator pedal angle.

The ECM monitors the accelerator pedal angle from VPA1 and VPA2 signal outputs, and controls the throttle actuator based on these signals.









HINT
After confirming DTC P2120, P2122, P2123, P2125, P2127, P2128 and P2138, use the Techstream to confirm the APP sensor output voltage.





MONITOR DESCRIPTION

When either voltage output VPA1 or VPA2 deviates from the standard range, 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 APP sensor. The ECM illuminates the MIL and sets a DTC.

Example:

When the voltage output of the VPA1 below 0.4 V or exceeds 4.8 V.

This monitor runs for 2 seconds (the first 2 seconds of engine idle) after the engine is started (1 trip detection logic).

MONITOR STRATEGY





TYPICAL ENABLING CONDITIONS





TYPICAL MALFUNCTION THRESHOLDS

P2120:





P2122:





P2123:





P2125:





P2127:





P2128:





P2138:





COMPONENT OPERATING RANGE





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 5 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: P2120, P2122, P2123, P2125, P2127, P2128 or P2138.

- 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.
FAIL-SAFE

The APP 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 two sensor circuits and changes to fail-safe mode. In fail-safe mode, the remaining 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 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





INSEPCTION PROCEDURE

HINT
- Read freeze frame data using the Techstream. Freeze frame data records the engine conditions when a malfunction is detected. When troubleshooting, freeze frame data can help determine if the vehicle was running or stopped, 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 is the repair procedure for the Accelerator Pedal Position (APP) sensor.
PROCEDURE

1. READ VALUE USING TECHSTREAM (ACCELERATOR POSITION SENSOR)

(a) Connect the Techstream to the DLC3.





(b) Turn the ignition switch to ON.

(c) Enter the following menus: Powertrain / Engine / Data List / Accel Sensor Out No. 1 and Accel Sensor Out No. 2.

(d) Read the Accel Sensor Out No. 1 and Accel Sensor Out No. 2 values.

Standard Voltage:





Result:





B -- READ OUTPUT DTC (ACCELERATOR PEDAL POSITION SENSOR DTCS ARE OUTPUT AGAIN)
A -- Continue to next step.

2. INSPECT ACCELERATOR PEDAL ROD ASSEMBLY (APP SENSOR)

(a) Disconnect the A14 APP sensor connector.





(b) Measure the resistance of the sensor.

Standard Resistance:





NG -- REPLACE ACCELERATOR PEDAL ROD ASSEMBLY
OK -- Continue to next step.

3. INSPECT ECM (VCPA, VCP2, VOLTAGE)

(a) Turn the ignition switch to ON.





(b) Measure the voltage of the ECM connector.

Standard Voltage:





NG -- REPLACE ECM Service and Repair
OK -- Continue to next step.

4. CHECK HARNESS AND CONNECTOR (APP SENSOR - ECM)

(a) Disconnect the A14 APP sensor connector.





(b) Disconnect the E5 ECM connector.

(c) Measure the resistance of the wire harness side connectors.

Standard Resistance:





NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR

OK -- REPLACE ACCELERATOR PEDAL ROD ASSEMBLY

5. READ 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 P2120, P2122, P2123, P2125, P2127, P2128 and P2138.

(c) Read the DTCs.

Result:





B -- CHECK FOR INTERMITTENT PROBLEM

A -- REPLACE ECM Service and Repair