Fault Conditions

O2S Heater Circuit. Current too High, Sensor 1.







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:
- Test 1: Engine running. Main relay voltage exceeding 10V. Pre-heating active.
- Test 2: Engine running. Main relay voltage exceeding 10V. Pre-heating active for more than 60 s.

Fault criteria:
- Test 1: Output voltage exceeding 2V for more than 5 s.
- Test 2: Current exceeding 2300 mA for more than 5 s.

Dependents:
- None.

System reaction to a fault:
- Closed loop is blocked.

OK report:
- Enable criteria fulfilled. Fault criteria for P0135 or P0136 not fulfilled within 60 s.

Fault handling: Fault Handling III, Other Emission-Related Component & 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.
- Activate output for pre-heating.
- Oxygen sensor pre-heating current, unit mA.

For information, Tech 2 Menu Structure, DTC Menu, Read Value, Activate, Sys Info

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 Preheating Power Supply