Diagnostic Trouble Code (DTC) Information

Diagnostic trouble code (DTC) information

Condition




Engine control module (ECM) monitors the rear heated oxygen sensor's heating coil and its ability to preheat the oxygen sensor. This is done to measure impedance across the heater circuit during the preheating sequence for the oxygen sensor.

Hint: The engine cylinders are counted from the cylinder furthest away from the flywheel.

The diagnostic trouble code (DTC) is stored if the control module detects that:
- Impedance in the heater circuit exceeds 60.3 ohms.
The control module's test for the diagnostic trouble code (DTC) starts in the event of:
- Ignition position II or engine running.

Substitute value
- None.

Possible source
- Contact resistance or oxidation in the terminals.
- Damaged rear heated oxygen sensor (HO2S).

Fault symptom[s]
- Warning lights and chimes/Malfunction Indicator Light ("Check engine" light) indication/no indication