Trouble Code Conditions

4-4-3 THREE-WAY CATALYTIC CONVERTER EFFICIENCY





Trouble Code Condition(s)
- The engine control module (ECM) continuously monitors three-way catalytic converter (TWC) efficiency by comparing the signal from the rear heated oxygen sensor (H02S) with the signal from the front heated oxygen sensor. When three-way catalytic converter efficiency deviates too much the engine control module stores diagnostic trouble code (DTC) EFI-443.

Substitute value(s)
- None.

Possible source(s)
- Uneven compression.
- Air leakage in the intake system.
- Air leakage in the exhaust system.
- Faulty fuel pressure.
- Defective three-way catalytic converter.

Fault symptom(s)
- May result in poor performance.
- Poorer cleaning of exhaust gases.