Diagnostic Trouble Code (DTC) Information

Diagnostic trouble code (DTC) information ECM-400C

Condition
The engine control module (ECM) continuously checks three-way catalytic converter (TWC) efficiency (bank 1) by comparing signals from the rear heated oxygen sensor (HO2S) with the signal from the front heated oxygen sensor (HO2S). The diagnostic trouble code (DTC) is stored if the efficiency of the three-way catalytic converter (TWC) deviates too much.
The diagnostic trouble code (DTC) is diagnosed when driving under specific driving conditions.

Substitute value
- The rear long-term fuel trim is disabled.

Possible source
- Misfiring
- Leakage in the intake system
- Leakage in the exhaust system
- Faulty fuel pressure
- Uneven compression
- Damaged catalytic converter.

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