Diagnostic Procedures
- Perform I/M system check. See INSPECTION/MAINTENANCE SYSTEM CHECK . After performing I/M system check, go to next step.
- Turn all accessories off. Start engine and allow to idle. Operate vehicle in the following conditions:
- Accelerate at part throttle to 55 MPH and maintain speed for 5 minutes.
- Decelerate to a stop. Allow engine to idle for 2 minutes with service brakes applied, A/T in Drive or M/T in Neutral.
- Using scan tool, monitor I/M System Status display. If catalyst system status updates to YES, go to step 5. If catalyst system status does not update to YES, go to next step.
- Using scan tool, observe DTC information. If scan tool indicates any failed DTCs, diagnose affected DTCs. See DIAGNOSTIC TROUBLE CODE DEFINITIONS . If scan tool does not indicate any failed DTCs, go to next step.
- Using scan tool, monitor DTC P0420. Operate vehicle within code enable criteria for DTC P0420. See DTC P0420 under DIAGNOSTIC TESTS. Operate vehicle within code enable criteria until scan tool indicates diagnostic test has run. Using scan tool, observe I/M System status. If catalyst system status is YES, go to next step. If catalyst system status is not YES, see DIAGNOSTIC AIDS .
- Using scan tool, check for DTCs. If scan tool indicates any DTCs are set, see DIAGNOSTIC TROUBLE CODE DEFINITIONS .