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

TROUBLE JUDGEMENT

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 FUNCTIONS

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 (main)
Open/short circuit or harness damage in accelerator pedal position sensor main 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. Voltage measurement at accelerator pedal position sensor connector (APS5 line).

(1)Disconnect the connector, and measure at the wiring harness side.

(2)Ignition switch: ON

(3)Check the voltage between the accelerator pedal position sensor connector (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 of open circuit, and short to earth in APS5 line between accelerator pedal position sensor connector and engine-ECU connector.

Q. Is the check result normal?

	Go to Step 4.

	Repair the connector(s) or wiring harness.

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 of damage in APS5 line between accelerator pedal position sensor connector and engine-ECU connector.

Q. Is the check result normal?

	Go to Step 6.

	Repair the connector(s) or wiring harness.

STEP 6. Check of open circuit, short to earth, and damage in APSM line between accelerator pedal position sensor connector and engine-ECU connector.

Q. Is the check result normal?

	Go to Step 7.

	Repair the connector(s) or wiring harness.

STEP 7. Replace the accelerator pedal assembly

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

Q. Is diagnosis code set?

	Replace the engine-ECU.

	Check end.