Self-Diagnostic System: Notes

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NOTE: Prizm 1.8L uses a Powertrain Control Module (PCM). All other models use a Engine Control Module (ECM). All references to ECM include PCM unless specified otherwise. All references to Prizm include all Prizm models unless specified otherwise.

The ECM is equipped with a self-diagnostic system, which detects system failures or abnormalities. When a malfunction occurs, ECM will illuminate the Malfunction Indicator Light (MIL) located on instrument cluster. When malfunction is detected and MIL is turned on, a corresponding DTC will be stored in ECM memory. To retrieve stored DTCs, see READING DTCS or RETRIEVING DTCS (NON-SCAN). Malfunctions are recorded as HARD FAILURES or as INTERMITTENT FAILURES. When ignition is turned to ON position, MIL will come on until engine is started as a bulb check.