Code No. P0158: Left Bank Oxygen Sensor (Rear) Circuit High Voltage

The sensor signal is inputted to the engine-ECU <M/T> or engine-A/T-ECU <A/T> (terminal No. 116) from the left bank oxygen sensor (rear) output terminal (terminal No. 4).
The left bank oxygen sensor (rear) (terminal No. 2) is earthed with engine-ECU <M/T> or engine-A/T-ECU <A/T> (terminal No. 96).

The left bank oxygen sensor (rear) converts the concentration of oxygen in the exhaust emission into a voltage and inputs the signal to the engine-ECU <M/T> or engine-A/T-ECU <A/T>.
When the air-fuel ratio is richer than the theoretical air-fuel ratio, the left bank oxygen sensor (rear) outputs a voltage of about 1 V. When it is leaner than the theoretical air-fuel ratio, it outputs a voltage of about 0 V.
In response to the signal, the engine-ECU <M/T> or engine-A/T-ECU <A/T> controls the fuel injection amount so that the air-fuel ratio can be equivalent to the theoretical air-fuel ratio.

Check Condition

Judgment Criterion

Failed left bank oxygen sensor (rear)
Open/short circuit in left bank oxygen sensor (rear) heater circuit or loose connector contact
Failed engine-ECU <M/T> or engine-A/T-ECU <A/T>

DIAGNOSIS PROCEDURE

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

	Go to Step 2 .

	Go to Step 3 .

	Repair or replace the connector.

	Go to Step 4 .

	Repair or replace the connector.

note

Before checking harness, check intermediate connector D-255, and repair if necessary.

	Go to Step 5 .

	Repair the damaged harness wire.

note

Before checking harness, check intermediate connectors D-111 and D-225, and repair if necessary.

	Go to Step 6 .

	Repair the damaged harness wire.

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

	Replace the engine-ECU <M/T> or engine-A/T-ECU <A/T>.