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. 151) 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 converts the opening degree of the accelerator pedal into the voltage signal to input it to the engine ECU.
  • The engine ECU uses this signal to determine the amount of basic fuel injection.

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.

FAIL-SAFE AND BACKUP FUNCTION



  • The amount of depression of the accelerator pedal is detected, using the accelerator pedal position sensor (sub) signal, which is calculated by taking half of the normal value.

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: C-23 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 C-23 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: B-10 engine-ECU connector

Q. Is the check result normal?
Go to Step 5 .
Repair or replace the connector.

STEP 5. Check harness between C-23 (terminal No. 2) accelerator pedal position sensor connector and B-10 (terminal No. 151) 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.

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.