Diagnostic Trouble Code (DTC) Information
Condition
Engine control module (ECM) checks the function of the rear heated oxygen sensor by monitoring how fast the sensor reacts when the system switches from rich to lean in case of a fuel shut-off.
The diagnostic trouble code (DTC) is stored if the control module detects that:
- Voltage across rear heated oxygen sensor drops too slowly.
- Slow voltage-drop in case of more than 10 subsequent fuel shut-offs during the same driving cycle.
The control module's test for the diagnostic trouble code (DTC) starts in the event of:
- Hot engine.
- Vehicle speed 70-90 km/h.
- Fuel shut-off.
NOTE:
The control module can only detect the fault once the test has been started and the diagnostic trouble code (DTC) is stored when the conditions are met.
Substitute Value
- None.
Possible Source
- Contact resistance, oxidation or poor contact in connections.
- Damaged rear heated oxygen sensor (HO2S).
Fault symptom[s]
- Malfunction indicator lamp (MIL) lit.