(VIN: -039999) Trionic T7 V6 OBD II (B308E)

P0138
02S Circuit. High Voltage. Sensor 2

Fault symptoms
- CHECK ENGINE.

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

Enable conditions:
- General conditions for this trouble code: When starting the engine, the atmospheric pressure must exceed 78 kPa and the engine coolant and intake air temperatures must exceed -7°C.
- Engine running. Main relay voltage exceeding 10V.

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.
- Type III.

Diagnostic help
Fault diagnosis concerns an electrical fault in connecting leads or in the sensor.
Functions in the diagnostic tool related to the fault:
- Diagnostic status for the diagnosis.
- Oxygen Sensor Value, unit V.

See also the description of readings in "Fault diagnosis, general" for more information.

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.

Checking the wiring
Jiggle the wiring harness at several points and in different directions to detect intermittent breaks and short circuits. Observe the multimeter, diagnostic tool or test lamp during the check.