Diagnostic Aids

Rough road conditions may prevent some tests from running. Extreme high or low ambient temperatures may prevent tests such as Heated Oxygen (HO2S) heater and Evaporative Emission (EVAP) System from initiating. If a step is interrupted before completion, perform the remaining portion of the set procedures. Any portion of the set procedure that requires the engine at operating temperature may be repeated. This allows most diagnostics to run and the remaining tests can be performed using the individual system set procedures.

The scan tool can be used to monitor each I/M SYSTEM STATUS indicators during the I/M complete system set procedure. When all indicators for a test step have updated to YES, testing can move on to the next step even if the remaining portion of the test is not complete. For example, step  3 is designed to run the catalyst test. The procedure instructs technician to operate the vehicle in enable conditions for 6 minutes. If the test updates to YES within 4 minutes, it is not necessary to continue with enable conditions and testing can advance to the next step.