Fault Conditions

P0138

O2S Circuit. High Voltage. Sensor 2.







Fault symptoms
- CHECK ENGINE.

On-Board Diagnostics
Type of diagnosis:
- Continuous. But interrupted when fault criteria fulfilled and will not restart until next driving cycle.

Enable criteria:
- General conditions for this trouble code: Atmospheric pressure must exceed 72 kPa and the engine coolant and intake air temperature must exceed -7 °C.
- Engine running. Main relay voltage exceeding 10 V.
- Engine load 150 mg/c. Coolant temperature more than 60 °C. Closed loop active longer than 5 s. Closed loop between 20 and -20%. No fuel shut-off.

Fault criteria:
- Voltage higher than 1.250 V for more than 2 s.

Dependents:
- P1141 and P1142.

System reaction to a fault:
- Transition adaptation of closed loop is blocked.

OK report:
- P0140 diagnosis performed once and fault criteria not fulfilled. Fault criteria for P0138 not fulfilled.

Fault handling: (See "Fault diagnosis, general" for more information.) Initial Inspection and Diagnostic Overview
- Type III.

Diagnostic help
Fault diagnosis concerns electrical faults in connected leads or in the sensor.

Diagnostic tool functions related to this fault are:
- Diagnostic status for the diagnosis. Heated oxygen sensor reading, in V.

See also the description of test values under "Fault diagnosis, general" for more information. Initial Inspection and Diagnostic Overview


NOTE: The oxygen sensor receives reference oxygen from the surrounding air via the connecting cables. For this reason, electrical contact spray or grease must not be used on the oxygen sensor connector.


Check the wiring
Jiggle the leads and in-line connectors at various points and in different directions to detect any intermittent breaks or short circuits in the wiring. Observe the multimeter, test lamp or diagnostic tool while doing this.