Diagnostic Trouble Code (DTC) Information

Diagnostic trouble code (DTC) information

Condition
The control module continuously checks three-way catalytic converter (TWC) efficiency by comparing signals from the rear heated oxygen sensor (HO2S) with the front heated oxygen sensor (HO2S). Diagnostic trouble code (DTC) ECM-4801 will be stored if the efficiency of the three-way catalytic converter (TWC) deviates too much.

Substitute value
Rear heated oxygen sensor (HO2S) control is disabled.

Possible source
- misfiring
- air leakage in the intake system
- air leakage in the exhaust system
- faulty fuel pressure
- uneven compression
- defective three-way catalytic converter (TWC).

Fault symptom[s]
- malfunction indicator lamp (MIL) lit.