Three Way Catalytic Converter, TWC Checking

Function

A catalytic converter is a vehicle emissions control device that converts toxic pollutants in exhaust gas to less toxic pollutants by catalyzing a redox reaction (oxidation or reduction). Catalytic converters are used in internal combustion engines.

General recommendations

Observe all safety precautions. Refer to: SAFETY PRECAUTIONS .

View clean working conditions. Refer to: CLEAN WORKING CONDITIONS .

Prior to repair work, perform a preliminary check to verify the condition. Refer to: PRELIMINARY CHECK .

Test requirements

Battery voltage at least 12.5 volts.
Oxygen sensors OK.
No leaks or damage to exhaust system.

Function test

Step	Procedure	Result / Action to Take
1	Activate Monitors: Perform the function test in Diagnostic Mode 06. Refer to:DIAGNOSTIC MODES 01 - 09 . End diagnosis and switch the ignition off. If the specified values are exceeded:	Check the exhaust system for leaks. If necessary, repair the leak(s) in the exhaust system. GO TO Step 2 THREE WAY CATALYTIC CONVERTER, TWC CHECKING .
2	O2 Sensor Monitoring: Erase the DTC memory. Refer to: DIAGNOSTIC MODE 04 - ERASE DTC MEMORY . Perform a road test to verify repair. If the DTC does not return:	Repair is complete. Generate readiness code. Refer to: READINESS CODE . If no leaks are found in the exhaust system: Replace the catalytic converter with front exhaust pipe. Refer to the appropriate repair service information. GO TO Step 3 THREE WAY CATALYTIC CONVERTER, TWC CHECKING .
3	Final procedure: Perform a road test to verify repair.	After the repair work, the following work steps must be performed in the following sequence: Check the DTC memory. Refer to DIAGNOSTIC MODE 03 - READ DTC MEMORY . If necessary, erase the DTC memory. Refer to: DIAGNOSTIC MODE 04 - ERASE DTC MEMORY . If the DTC memory was erased, generate readiness code. Refer to: READINESS CODE . Return vehicle to Customer.