Code No. P2253: Oxygen Sensor Offset Circuit High Voltage


OPERATION



  • Check code No. P0131: oxygen sensor (front) circuit low voltage (Refer to ).
  • Check code No. P0137: oxygen sensor (rear) circuit low voltage (Refer to ).

FUNCTION



  • The engine-ECU watches and checks whether the offset voltage of the oxygen sensor is normal or not.

TROUBLE JUDGMENT


Check Condition
  • More than 2 seconds have passed since the engine starting sequence was completed.
Judgement Criterion
  • Oxygen sensor offset voltage is more than 0.6 V for 2 seconds.
FAIL-SAFE AND BACKUP FUNCTION
  • Does not control air-fuel ratio closed loop.

PROBABLE CAUSES



  • Failed oxygen sensor (front)
  • Failed oxygen sensor (rear)
  • Short circuit in oxygen sensor (front) circuit or loose connector contact
  • Short circuit in oxygen sensor (rear) circuit or loose connector contact
  • Failed engine-ECU

DIAGNOSIS PROCEDURE

STEP 1. Check oxygen sensor (front) itself.

  • Oxygen sensor (front) connector check.
  • Oxygen sensor check (Refer to ).

Q. Is the check result normal?
Go to Step 2.
Repair or replace the connector, or replace the oxygen sensor (front).

STEP 2. Check oxygen sensor (rear) itself.

  • Oxygen sensor (rear) connector check.
  • Oxygen sensor check (Refer to ).

Q. Is the check result normal?
Go to Step 3.
Repair or replace the connector, or replace the oxygen sensor (rear).

STEP 3. Perform voltage measurement at engine-ECU connector.

  • Disconnect engine-ECU connector, and connect special tool power plant ECU check harness (MB992110) to measure at connector for inspection.
  • Ignition switch: "ON"
  • Voltage between terminal OFLE and body earth.
OK: 0.4 - 0.6 V

Q. Is the check result normal?
Go to Step 7.
Go to Step 4.

STEP 4. Check harness between oxygen sensor (front) connector terminal and engine-ECU connector terminal OFLE.

  • Check earthing line for short circuit.

Q. Is the check result normal?
Go to Step 5.
Repair or replace the connector, or repair the damaged harness wire.

STEP 5. Check harness between oxygen sensor (front) connector terminal and engine-ECU connector terminal O2FL.

  • Check output line for short circuit.

Q. Is the check result normal?
Go to Step 6.
Repair or replace the connector, or repair the damaged harness wire.

STEP 6. M.U.T.-III diagnosis code

  • Reconfirmation of diagnosis code.

Q. Is the diagnosis code set?
Replace the engine-ECU.
Intermittent malfunction (Refer to GROUP 00 - How to Use Troubleshooting/Inspection Service Points - How to Cope with Intermittent Malfunctions ).

STEP 7. Perform voltage measurement at engine-ECU connector.

  • Disconnect engine-ECU connector, and connect special tool power plant ECU check harness (MB992110) to measure at connector for inspection.
  • Ignition switch: "ON"
  • Voltage between terminal ORLE and body earth.
OK: 0.4 - 0.6 V

Q. Is the check result normal?
Go to Step 6.
Go to Step 8.

STEP 8. Check harness between oxygen sensor (rear) connector terminal and engine-ECU connector terminal ORLE.

  • Check earthing line for short circuit.

Q. Is the check result normal?
Go to Step 9.
Repair or replace the connector, or repair the damaged harness wire.

STEP 9. Check harness between oxygen sensor (rear) connector terminal and engine-ECU connector terminal O2RL.

  • Check output line for short circuit.

Q. Is the check result normal?
Go to Step 6.
Repair or replace the connector, or repair the damaged harness wire.