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. 149).
  • The power voltage is earthed to the engine-ECU (terminal No. 136) from the accelerator pedal position sensor (terminal No. 2).
  • The sensor signal is inputted to the engine-ECU (terminal No. 150) 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.
  • Diagnosis code 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 or harness damage 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

  1. Item 9: 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. 136) 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 .

  1. Item 9: 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 ). After registering the injector identification code, the vehicle equipped with the closed type DPF carries out the forcible DPF regeneration. (Refer to GROUP 17 - Diesel Particulate Filter (DPF) System - Forcible DPF Regeneration ).

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 ). After registering the injector identification code, the vehicle equipped with the closed type DPF carries out the forcible DPF regeneration. (Refer to GROUP 17 - Diesel Particulate Filter (DPF) System - Forcible DPF Regeneration ).