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Home >> Geo >> 1994 >> Prizm Base, Standard >> Repair and Diagnosis >> Engine Performance >> System >> Engine Controls - Tests W/Codes >> Self-Diagnostic System >> Retrieving Codes (Non-Scan)
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Retrieving Codes (Non-Scan)

All vehicles are equipped with a Malfunction Indicator Light (MIL), located on instrument cluster. Light comes on, as a bulb check, when ignition switch is turned to ON position and engine is not running. Light should not flash at this time and should go out when engine is started.

If MIL remains on or flashes with engine running, self-diagnostic system has detected a problem. If problem goes away, light will go out after 10 seconds, but a fault code will be stored in ECM memory.

All trouble codes except Code 16 (PCM control signal on Prizm LSi), Code 43 (crank signal) and Code 51 (switch condition signal) are stored in ECM memory. Codes 16, 43 and 51 are erased from memory as soon as ignition is turned off. To detect an active Code 16, 43 or 51, turn ignition switch to ON position (engine off) with diagnostic request terminal TE1 in Data Link Connector (DLC) grounded. See Figure . DLC is located on left shock tower. If ignition switch is turned to OFF position at any time during this procedure, a hard or active Code 16, 43 or 51 will be lost.