DTC ECM-4801

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.