Code No. P0154: Left Bank Oxygen Sensor (Front) Circuit No Activity Detected <Except Euro 2>

OPERATION

Check code No. P0151: left bank oxygen sensor (front) circuit low voltage (Refer to ).
Check code No. P0264: No. 2 injector circuit low input (Refer to ).
Check code No. P0270: No. 4 injector circuit low input (Refer to ).
Check code No. P0276: No. 6 injector circuit low input (Refer to ).

FUNCTION

The engine-ECU 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 JUDGEMENT

Check Conditions

Typically 20 seconds have passed since the engine starting sequence was completed.
Engine coolant temperature is more than 76°C.
Engine speed is more than 1,200 r/min.
Volumetric efficiency is more than 30 %.
Except while fuel is being shut off.
Monitoring time: 30 seconds.

Judgement Criterion

Left bank oxygen sensor (front) output voltage does not get across lean/rich criteria (about 0.5 V) within about 30 seconds.

FAIL-SAFE AND BACKUP FUNCTION

None

PROBABLE CAUSES

Failed left bank oxygen sensor (front)
Harness damage in left bank oxygen sensor (front) circuit
Failed left bank injector
Harness damage in left bank injector circuit
Exhaust leak
Air drawn in from gaps in gasket, seals, etc.
Incorrect fuel pressure
Failed engine-ECU

DIAGNOSIS PROCEDURE

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

Data list reference table (Refer to ).

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. Check left bank oxygen sensor (front) itself.

Left bank oxygen sensor (front) check (Refer to ).

Q. Is the check result normal?

	Go to Step 5.

	Replace the left bank oxygen sensor (front).

STEP 5. Check No. 2, No. 4 and No. 6 injector itself.

No. 2, No. 4 and No. 6 injector check (Refer to ).

Q. Are the check results normal?

	Go to Step 6.

	Replace the injectors.

STEP 6. Check of damage in O2FL line between left bank oxygen sensor (front) connector and engine-ECU connector.

Q. Is the check result normal?

	Go to Step 7.

	Repair the connector(s) or wiring harness.

STEP 7. Check of damage in INJ2, INJ4 and INJ6 line between injector connectors and engine-ECU connector.

Q. Are the check result normal?

	Go to Step 8.

	Repair the connector(s) or wiring harness.

STEP 8. Fuel pressure measurement.

Fuel pressure test (Refer to ).

Q. Is the check result normal?

	Replace the engine-ECU.

	Repair.