Conditions

O2S Heater Circuit. Current too Low, 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 not active.
- Test 2: Engine running. Main relay voltage exceeding 10V. Pre-heating active.

Fault criteria:
- Test 1: Output voltage below 2V for more than 5 s.
- Test 2: Current below 300 mA for more than 5 s.

Dependents:
- P1641, P1654 and P1655.

System reaction to a fault:
- Closed loop control system 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 Comp. & Function
- 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.
- Activation of output for preheating.
- Oxygen sensor pre-heating current, unit mA.

See also the description of activating functions under "Fault diagnosis, general" for more information.
Tech 2 Menu Structure, DTC Menu, Read Value, Activate, Sys Info

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

Proceed to Diagnostic Procedures Checking the Sensor Preheating Power Supply