Code No. P2123: Accelerator Pedal Position Sensor (main) Circuit High Input

OPERATION

A power voltage of 5 V is applied to the accelerator pedal position sensor (terminal No. 1) from the engine-ECU (terminal No. 120).
The power voltage is earthed to the engine-ECU (terminal No. 122) from the accelerator pedal position sensor (terminal No. 2).
The sensor signal is inputted to the engine-ECU (terminal No. 121) from the accelerator pedal position sensor output terminal (terminal No. 3).

FUNCTION

The accelerator pedal position sensor (main) outputs voltage which corresponds to the accelerator pedal depression.
The engine-ECU checks whether the voltage is within a specified range.

TROUBLE JUDGMENT

Check Conditions

Ignition switch is in "ON" position
Accelerator pedal position sensor (sub) is normal
Accelerator pedal position sensor (sub) output voltage is 0.125 V or higher and 1.4 V or lower.
DTC No. P2124 is memorized.

Judgment Criterion

Accelerator pedal position sensor (main) output voltage is 4.8 V or more.

PROBABLE CAUSES

Failed accelerator pedal position sensor
Open circuit in accelerator pedal position sensor circuit or loose connector contact
Failed engine-ECU

DIAGNOSIS PROCEDURE

STEP 1. M.U.T.-III data list

Refer to Data List Reference Table

Item 09: Accelerator pedal position sensor (main)

Q. Is the check result normal?

	Intermittent malfunction (Refer to GROUP 00 - How to Use Troubleshooting/Inspection Service Points - How to Cope with Intermittent Malfunctions ).

	Go to Step 2.

STEP 2. Connector check: D-202 accelerator pedal position sensor connector

Q. Is the check result normal?

	Go to Step 3.

	Repair or replace the connector.

STEP 3. Perform resistance measurement at D-202 accelerator pedal position sensor connector.

Disconnect connector, and measure at harness side.
Resistance between terminal No. 2 and earth.

OK: Continuity (2 Ω or less)

Q. Is the check result normal?

	Go to Step 7.

	Go to Step 4.

STEP 4. Connector check: D-215 engine-ECU connector

Q. Is the check result normal?

	Go to Step 5.

	Repair or replace the connector.

STEP 5. Check harness between D-202 (terminal No. 2) accelerator pedal position sensor connector and D-215 (terminal No. 122) engine-ECU connector.

Check earthing line for open circuit and damage.

Q. Is the check result normal?

	Go to Step 6.

	Repair the damaged harness wire.

STEP 6. M.U.T.-III data list

Refer to Data List Reference Table .

Item 09: Accelerator pedal position sensor (main)

Q. Is the check result normal?

	Intermittent malfunction (Refer to GROUP 00 - How to Use Troubleshooting/Inspection Service Points - How to Cope with Intermittent Malfunctions ).

	Replace the engine-ECU. When the engine-ECU is replaced, write the chassis number (Refer to GROUP 00 - Precautions Before Service - How to Perform Chassis Number Writing ). After replacing the engine-ECU, register the injector identification code and learn fuel injection (Refer to GROUP 00 - Precautions Before Service - What The Common Rail Engine Learns ).

STEP 7. Replace the accelerator pedal assembly

After replacing the accelerator pedal assembly, re-check the trouble symptoms.

Q. Is the check result normal?

	The check is end.

	Replace the engine-ECU. When the engine-ECU is replaced, write the chassis number (Refer to GROUP 00 - Precautions Before Service - How to Perform Chassis Number Writing ). After replacing the engine-ECU, register the injector identification code and learn fuel injection (Refer to GROUP 00 - Precautions Before Service - What The Common Rail Engine Learns ).