Code No. P0134: Oxygen Sensor (Front) Circuit No Activity Detected










OPERATION



  • Refer to Code No. P0131: Oxygen sensor (front) circuit .
  • Refer to Code No. P0201: No. 1 injector system .
  • Refer to Code No. P0202: No. 2 injector system .
  • Refer to Code No. P0203: No. 3 injector system .
  • Refer to Code No. P0204: No. 4 injector system .

FUNCTION



  • The engine-ECU effects air/fuel ratio feedback control in accordance with the signals from the oxygen sensor (front).
  • If the oxygen sensor (front) has deteriorated, corrections will be made by the oxygen sensor (rear).
  • Code No. P0134 becomes stored in memory if a failure is detected in the above air/fuel ratio feedback control system.

TROUBLE JUDGMENT


Check Conditions
  • Engine coolant temperature is higher than 60°C.
  • Engine speed is higher than 1,200 r/min.
  • Volumetric efficiency is higher than 30 %.
  • Except while fuel is being shut off.
  • Monitoring time: 30 seconds.
Judgement Criterion
  • Oxygen sensor (front) output voltage does not get across lean/rich criteria (about 0.5 V) within about 30 seconds.

PROBABLE CAUSES



  • Failed oxygen sensor (front)
  • Harness damage in injector circuit or loose connector contact
  • Exhaust leak
  • Incorrect fuel pressure
  • Failed engine-ECU

DIAGNOSIS PROCEDURE

STEP 1. M.U.T.-III data list

  • Refer to Data List Reference Table .

  1. Item AC: Oxygen sensor (front)

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. Check for exhaust leaks.

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

STEP 3. Check for intake system vacuum leak.

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

STEP 4. Connector check: C-134 oxygen sensor (front) connector

Q. Is the check result normal?
Go to Step 5 .
Repair or replace the connector.

STEP 5. Check oxygen sensor (front) itself.

  • Check oxygen sensor (front) itself (Refer to Oxygen Sensor Check ).

Q. Is the check result normal?
Go to Step 6 .
Replace the oxygen sensor (front).

STEP 6. Connector check: A-13 intermediate connector.


Q. Is the check result normal?
Go to Step 7 .
Repair or replace the connector.

STEP 7. Check harness between A-13 intermediate connector and injector connector.

  1. Check and repair harness between A-13 (terminal No. 7) intermediate connector and B-102 (terminal No. 1) No. 1 injector connector.
  2. Check and repair harness between A-13 (terminal No. 7) intermediate connector and B-104 (terminal No. 1) No. 2 injector connector.
  3. Check and repair harness between A-13 (terminal No. 7) intermediate connector and B-105 (terminal No. 1) No. 3 injector connector.
  4. Check and repair harness between A-13 (terminal No. 7) intermediate connector and B-106 (terminal No. 1) No. 4 injector connector.

  • Check power supply line for damage.

Q. Are the check results normal?
Go to Step 8 .
Repair the damaged harness wire.

STEP 8. Connector check: Injector connector.



  • B-102 (No. 1 injector connector).
  • B-104 (No. 2 injector connector).
  • B-105 (No. 3 injector connector).
  • B-106 (No. 4 injector connector).

Q. Are the check results normal?
Go to Step 9 .
Repair or replace the connector.

STEP 9. Check injector itself.

  • Check injector itself (Refer to Injector Check ).

Q. Is the check result normal?
Go to Step 10 .
Replace the injector.

STEP 10. Connector check: B-29 engine-ECU connector.

Q. Is the check result normal?
Go to Step 11 .
Repair or replace the connector.

STEP 11. Check harness between C-134 (terminal No. 3) oxygen sensor (front) connector and B-29 (terminal No. 38) engine-ECU connector.
note Before checking harness, check intermediate connector A-13 and repair if necessary.

  • Check output line for damage.

Q. Is the check result normal?
Go to Step 12 .
Repair the damaged harness wire.

STEP 12. Check harness between injector connector and engine-ECU connector.

  1. Check and repair harness between B-102 (terminal No. 2) No. 1 injector connector and B-29 (terminal No. 2) engine-ECU connector.
  2. Check and repair harness between B-104 (terminal No. 2) No. 2 injector connector and B-29 (terminal No. 3) engine-ECU connector.
  3. Check and repair harness between B-105 (terminal No. 2) No. 3 injector connector and B-29 (terminal No. 18) engine-ECU connector.
  4. Check and repair harness between B-106 (terminal No. 2) No. 4 injector connector and B-29 (terminal No. 19) engine-ECU connector.

  • Check output line for damage.

Q. Are the check results normal?
Go to Step 13 .
Repair the damaged harness wire.

STEP 13. Fuel pressure measurement.

  • Fuel pressure measurement (Refer to Fuel Pressure Test ).

Q. Is the check result normal?
Replace the engine-ECU.
Repair.