P0157

* When these faults occur, the fault codes P1115 and P1119 may be stored in addition; however, these faults are no actual faults.
** When this fault occurs, all the four oxygen sensors are stored.

P0157
Oxygen Sensor Behind Catalytic Converter (Cylinders 4 - 6) - Short Circuit to Ground at Signal Wire or Incorrect Voltage.

Function:
To diagnose the readiness for operation of the oxygen sensors, the position of the sensor voltage is evaluated (in case of certain faults or conditions, the diagnosis is disabled).

Diagnosis Conditions:
Diagnostic Trouble Code P0157 is stored in the ECM, when the sensor voltage is below - 150 mV.

Conditions for the diagnosis of the oxygen sensor signals:

- Sensor heating is active.

NOTE: When DTC P0157 is stored and faults of the heating of the other three oxygen sensors are displayed, only one oxygen sensor is probably faulty.

Wiring Diagram:




Diagnosis Procedure:



1. Check wiring harness>
1. Remove all the four oxygen sensor connectors.
2. Switch ignition on.
3. Connect voltmeter at sleeve to pins 3 and 4 of oxygen sensor connector 2 behind catalytic converter.

Specified Value: approx. 450 mV.

4. Connect voltmeter at sleeve to pin 3 and ground.

Specified Value: approx. 720 mV.

If the measurement according to items 3 and 4 does not show the specified values, remove ECM connector and check wires for short circuit to ground.

If no short circuit to ground can be detected, replace ECM.

2. Check oxygen sensor.
1. Remove oxygen sensor connector 2 behind catalytic converter.
2. Connect ohmmeter on pin side to pin 3 and the oxygen sensor housing.

Specified Value: Infinity Ohms.

3. Connect ohmmeter on pin side to pin 4 and the oxygen sensor housing.

Specified Value: Infinity Ohms.

4. Connect ohmmeter on pin side to pins 4 and 2.

Specified Value: Infinity Ohms.

5. Connect ohmmeter on pin side to pins 3 and 2.

Specified Value: Infinity Ohms.