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 connector terminal from the engine-ECU connector terminal APS5.
  • The power voltage is earthed to the engine-ECU connector terminal APSE from the accelerator pedal position sensor connector terminal.
  • The sensor signal is inputted to the engine-ECU connector terminal APSM from the accelerator pedal position sensor output terminal.

FUNCTION



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

TROUBLE JUDGMENT


Check Condition
  • Ignition switch is "ON" position.
Judgement Criterion
  • Accelerator pedal position sensor (main) output voltage is more than 4.8 V.

FAIL-SAFE AND BACKUP FUNCTION



  • Throttle opening degree is restricted.
  • Throttle opening degree position is in default position if accelerator pedal position sensor (sub) fails.

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

  • Data list reference table (Refer to ).

  1. Item 11: 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. Perform resistance measurement at accelerator pedal position sensor connector.

  • Disconnect connector, and measure at harness side.
  • Resistance between terminal engine-ECU APSE line and body earth.
OK: Continuity (2 Ω or less)

Q. Is the check result normal?
Go to Step 5.
Go to Step 3.

STEP 3. Check harness between accelerator pedal position sensor connector terminal and engine-ECU connector terminal APSE.

  • Check earthing line for open circuit and damage.

Q. Is the check result normal?
Go to Step 4.
Repair or replace the connector, or repair the damaged harness wire.

STEP 4. M.U.T.-III data list

  • Data list reference table (Refer to ).

  1. Item 11: 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 5. Replace the accelerator pedal assembly

  • After replacing the accelerator pedal assembly, reconfirm whether the diagnosis code is set.

Q. Is the diagnosis code set?
Replace the engine-ECU.
Check end.