Code No. P2122: Accelerator Pedal Position Sensor (main) Circuit Low 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 less than 0.2 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/short 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 ).

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 voltage measurement at accelerator pedal position sensor connector.

Disconnect connector, and measure at harness side.
Ignition switch: "ON"
Voltage between terminal engine-ECU APS5 line and body earth.

OK: 4.9 - 5.1 V

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 APS5.

Check power supply line for open/short circuit.

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 ).

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. Check harness between accelerator pedal position sensor connector terminal and engine-ECU connector terminal APS5.

Check power supply line for damage.

Q. Is the check result normal?

	Go to Step 6.

	Repair or replace the connector, or repair the damaged harness wire.

STEP 6. Check harness between accelerator pedal position sensor connector terminal and engine-ECU connector terminal APSM.

Check output line for open/short circuit and damage.

Q. Is the check result normal?

	Go to Step 7.

	Repair or replace the connector, or repair the damaged harness wire.

STEP 7. 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.