Code No. P0154: Left Bank Oxygen Sensor (Front) Circuit No Activity Detected












OPERATION



  • Refer to Code No. P0150: Left bank oxygen sensor (front) circuit .
  • Refer to Code No. P0202: No. 2 injector system .
  • Refer to Code No. P0204: No. 4 injector system .
  • Refer to Code No. P0206: No. 6 injector system .

FUNCTION



  • The engine-ECU <M/T> or engine-A/T-ECU <A/T> effects air/fuel ratio feedback control in accordance with the signals from the left bank oxygen sensor (front).
  • If the left bank oxygen sensor (front) has deteriorated, corrections will be made by the left bank oxygen sensor (rear).
  • Code No. P0154 becomes stored in memory if a failure is detected in the above air/fuel ratio feedback control system.

TROUBLE JUDGMENT


Check Conditions
  • 20 seconds or more have passed since the engine starting sequence was completed.
  • Engine coolant temperature is 76°C or more.
  • Engine speed is higher than 1,200 r/min.
  • Volumetric efficiency is 30 % or more.
  • Throttle position sensor output voltage is 4 V or less.
  • Except while fuel is being shut off.
Judgment Criterion
  • Left bank oxygen sensor (front) output voltage does not get across approximately 0.5 V within about 30 seconds.

PROBABLE CAUSES



  • Failed left bank oxygen sensor (front)
  • Exhaust leak
  • Incorrect fuel pressure
  • Failed engine-ECU <M/T> or engine-A/T-ECU <A/T>

DIAGNOSIS PROCEDURE

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

  • Refer to Data List Reference Table .

  1. Item AE: Left bank 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: B-23 left bank oxygen sensor (front) connector

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

STEP 5. Check left bank oxygen sensor (front) itself.

  • Check left bank oxygen sensor (front) itself (Refer to ).

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

STEP 6. Connector check: B-48 intermediate connector.


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

STEP 7. Perform resistance measurement at B-48 intermediate connector.

  1. Measure the resistance between terminal No. 2 and No. 8 when measuring No. 2 cylinder.
  2. Measure the resistance between terminal No. 7 and No. 8 when measuring No. 4 cylinder.
  3. Measure the resistance between terminal No. 5 and No. 8 when measuring No. 6 cylinder.
OK: 10.5 - 13.5 Ω (20°C)

Q. Are the check results normal?
Go to Step 10 .
Go to Step 8 .

STEP 8. Connector check: Injector connector.



  • B-111 (No. 2 injector connector).
  • B-105 (No. 4 injector connector).
  • B-104 (No. 6 injector connector).

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

STEP 9. Check No. 2, No. 4 and No. 6 injector itself.
Check No. 2, No. 4 and No. 6 injector itself (Refer to

Q. Is the check result normal?

    Check and repair harness between injector intermediate connector and injector connector.

  1. Check and repair harness between B-48 (terminal No. 2) injector intermediate connector and B-111 (terminal No. 2) No. 2 injector connector
  2. Check and repair harness between B-48 (terminal No. 7) injector intermediate connector and B-105 (terminal No. 2) No. 4 injector connector
  3. Check and repair harness between B-48 (terminal No. 5) injector intermediate connector and B-104 (terminal No. 2) No. 6 injector connector

  • Check output line for damage.
Replace the injector.

STEP 10. Connector check: D-246 engine-ECU <M/T> connector or D-217 engine-A/T-ECU <A/T> connector.

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

STEP 11. Check harness between B-23 (terminal No. 4) left bank oxygen sensor (front) connector and D-246 (terminal No. 108) engine-ECU <M/T> connector or D-217 (terminal No. 108) engine-A/T-ECU <A/T> connector.

  • 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 No. 2, No. 4 and No. 6 injector connector and engine-ECU <M/T> or engine-A/T-ECU <A/T> connector.



  1. Check and repair harness between B-111 (terminal No. 2) No. 2 injector connector and D-243 (terminal No. 5) engine-ECU <M/T> connector or D-212 (terminal No. 5) engine-A/T-ECU <A/T> connector.
  2. Check and repair harness between B-105 (terminal No. 2) No. 4 injector connector and D-243 (terminal No. 21) engine-ECU <M/T> connector or D-212 (terminal No. 21) engine-A/T-ECU <A/T> connector.
  3. Check and repair harness between B-104 (terminal No. 2) No. 6 injector connector and D-243 (terminal No. 6) engine-ECU <M/T> connector or D-212 (terminal No. 6) engine-A/T-ECU <A/T> 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 ).

Q. Is the check result normal?
Replace the engine-ECU <M/T> or engine-A/T-ECU <A/T>.
Repair.