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 condition for this diagnostic trouble code: Atmospheric pressure must exceed 72 kPa as well as coolant and intake air temperature must exceed -7 degree C.
- Engine running. Main relay voltage exceeding 10 V.

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: (For more information, Fault Handling III, Other Emission-Related Components and Function)

- 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.

For more information, refer to scan tool testing. Menu Read Values

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.

Proceed to Diagnostic Procedures Checking the Sensor's Grounding