Diagnostic Aids

This chart will diagnose any injector circuit problems. Trouble with the fuel pump circuit and control relay can be diagnosed in CHART A-7A  .

Be sure to perform the ECM CIRCUIT RESISTANCE CHECK before replacing the ECM to prevent damage to the ECM.

Fig 1: Fuel Injection Circuit

Courtesy of GENERAL MOTORS CORP.

Fig 2: Chart A-5 Diagnostic Flow Chart

Courtesy of GENERAL MOTORS CORP.