Permanent Fault

ECM-4801 THREE-WAY CATALYTIC CONVERTER (TWC) EFFICIENCY
PERMANENT FAULT

Checking for air leakage in the intake system



Check for air leakage according to Check For Air Leaks In the Intake System

Remedy as necessary.

Was there any air leakage?
Yes - Skip to "Verification"
No - Continue below.


Checking for air leakage in the exhaust system



Check for air leakage according to Checking For Air Leakage In the Exhaust System

Remedy as necessary.

Was there any air leakage?
Yes - Skip to "Verification"
No - Continue below.


Checking fuel and residual pressures



Check fuel and residual pressure according to Checking Fuel and Residual Pressures

Remedy as necessary.

Was the pressure OK?
Yes - Continue below.
No - Skip to "Verification"


Checking compression



Carry out a compression test according to Compression Test

Remedy as necessary.

Was compression OK?
Yes - Continue below.
No - Skip to "Verification"


Replacing component
- Try a new three-way catalytic converter (TWC).


Verification



Hint: After carrying out the repair, check that the fault has been remedied as follows:

- Ignition off.
- Replace connector, components etc.

Note: After test driving the engine should not be turned off. Information in the control module is erased.

- Connect VCT 2000 to the data link connector (DLC).
- Read the status of the diagnostic trouble code (DTC). The text NOT READY is displayed if the diagnosis is still on-going. This indicates that the test drive was too short.

Is FAULT NOT REGISTERED displayed?
Yes - Test Complete.
No - Continue below.


Fault-tracing information
The fault should have been detected and remedied. As this is not the case fault-tracing has failed. Exit fault tracing for this diagnostic trouble code (DTC) or make another attempt.