Diagnostic Aids

The PCM has integrated circuits that are protected, therefore, if a circuit has failed, the IC may not be damaged and will keep the circuit open until the fault in the circuit has been corrected. When the fault has been corrected, reinstall PCM and check circuit. Replace PCM only if circuit is still operative.

Fig 1: Chart A-4, Injector Circuit Diagnosis (TBI)

Courtesy of GENERAL MOTORS CORP.

Fig 2: Chart A-4 Schematic, Injector Circuit Diagnosis (TBI)

Courtesy of GENERAL MOTORS CORP.

Fig 3: Chart A-4, Injector Circuit Diagnosis (CPI)

Courtesy of GENERAL MOTORS CORP.

Fig 4: Chart A-4 Schematic, Injector Circuit Diagnosis (CPI)

Courtesy of GENERAL MOTORS CORP.