Code No. P2138: Accelerator Pedal Position Sensor (Main and Sub) Range/Performance Problem

OPERATION

Refer to Code No. P2122: Accelerator Pedal Position Sensor (main) Circuit Low Input .
Refer to Code No. P2127: Accelerator Pedal Position Sensor (sub) Circuit Low Input .

FUNCTION

Engine-ECU checks the accelerator pedal position sensor output signal characteristics for abnormal conditions.

TROUBLE JUDGMENT

Check Condition

Ignition switch is in "ON" position.

Judgment Criterion

When an error is detected on the High side of the accelerator pedal position (main) for 0.1 second, the accelerator pedal position sensor (sub) is faulty on the High/Low side.

Check Conditions

Battery positive voltage is 6 - 16 V
2 seconds later after the ignition switch has been in "ON" position or the engine has started up
Engine speed is 600 r/min or more.
Accelerator pedal position sensor (main) output voltage is 0.2 V or higher and 4.8 V or lower.
Accelerator pedal position sensor (sub) output voltage is 0.125 V or higher and 2.375 V or lower.

Judgment Criterion

When a change in the accelerator pedal position sensor (sub) output voltage is less than the specified value for 0.2 second, the difference between the opening indicated by the accelerator pedal position sensor (main) and that by the accelerator pedal position sensor (sub) is 18 % or more of the specified value.

PROBABLE CAUSES

Failed accelerator pedal position sensor
Open/short circuit in accelerator pedal position sensor circuit or loose connector contact
Failed engine-ECU

DIAGNOSIS PROCEDURE

STEP 1. Connector check: C-115 accelerator pedal position connector

Q. Is the check result normal?

Go to Step 2 .

Repair or replace the connector.

STEP 2. Perform resistance measurement at C-115 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 4 .

Go to Step 3 .

STEP 3. Connector check: C-103 engine-ECU connector

Q. Is the check result normal?

Check earthing line for damage.

Repair or replace the connector.

STEP 4. Perform resistance measurement at C-115 accelerator pedal position sensor connector.

Disconnect connector, and measure at harness side.
Resistance between terminal No. 5 and earth.

OK: Continuity (2 Ω or less)

Q. Is the check result normal?

Go to Step 6 .

Go to Step 5 .

STEP 5. Connector check: C-103 engine-ECU connector

Q. Is the check result normal?

Check earthing line for damage.

Repair or replace the connector.

STEP 6. Perform voltage measurement at C-115 accelerator pedal position sensor connector.

Use special tool test harness (MB991658) to connect connector, and measure at pick-up harness.
Ignition switch: ON
Voltage between terminal No. 1 and earth.

OK: 4.9 - 5.1 V

Q. Is the check result normal?

Go to Step 8 .

Go to Step 7 .

STEP 7. Connector check: C-103 engine-ECU connector

Q. Is the check result normal?

Check power supply line for damage.

Repair or replace the connector.

STEP 8. Perform voltage measurement at C-115 accelerator pedal position sensor connector.

Use special tool test harness (MB991658) to connect connector, and measure at pick-up harness.
Ignition switch: ON
Voltage between terminal No. 4 and earth.

OK: 4.9 - 5.1 V

Q. Is the check result normal?

Go to Step 10 .

Go to Step 9 .

STEP 9. Connector check: C-103 engine-ECU connector

Q. Is the check result normal?

Check power supply line for damage.

Repair or replace the connector.

STEP 10. Perform voltage measurement at C-103 engine-ECU connector.

Measure engine-ECU terminal voltage.
Ignition switch: ON
Voltage between terminal No. 121 and earth.

OK: 0.7 - 1.3 V

Q. Is the check result normal?

Go to Step 12 .

Go to Step 11 .

STEP 11. Check harness between C-115 (terminal No. 3) accelerator pedal position sensor connector and C-103 (terminal No. 121) engine-ECU connector.

Check output line for damage.

Q. Is the check result normal?

Replace the accelerator pedal position sensor.

Repair the damaged harness wire.

STEP 12. Perform voltage measurement at C-103 engine-ECU connector.

Measure engine-ECU terminal voltage.
Ignition switch: ON
Voltage between terminal No. 113 and earth.

OK: 0.2 - 0.8 V

Q. Is the check result normal?

Go to Step 14 .

Go to Step 13 .

STEP 13. Check harness between C-115 (terminal No. 6) accelerator pedal position sensor connector and C-103 (terminal No. 113) engine-ECU connector.

Check output line for damage.

Q. Is the check result normal?

Replace the accelerator pedal position sensor.

Repair the damaged harness wire.

STEP 14. Connector check: C-103 engine-ECU connector

Q. Is the check result normal?

Go to Step 15 .

Repair or replace the connector.

STEP 15. M.U.T.-III diagnosis code

Reconfirmation of diagnosis code.

Q. Is the diagnosis code set?

	Replace the engine-ECU. When the engine-ECU is replaced, write the chassis number (Refer to GROUP 00 - 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 ).

	Intermittent malfunction (Refer to GROUP 00 - How to Use Troubleshooting/Inspection Service Points - How to Cope with Intermittent Malfunctions ).