Systems Tests: Notes
CAUTION:
When battery or ECM is disconnected, vehicle computer and memory systems may lose memory data. Driveability problems may exist until adaptation systems have completed a relearn cycle. See COMPUTER RELEARN PROCEDURES
article in GENERAL INFORMATION before disconnecting battery.
NOTE:
Before replacing any component that scan tool suggests are faulty. Ensure that all wiring connections and harness connectors are okay. Ensure that power and ground circuits are functioning properly. To identify ECM terminals referenced in testing, see PIN VOLTAGE/CIRCUIT RESISTANCE CHARTS
article. To identify circuits and wire colors referenced in testing, see ENGINE PERFORMANCE
in SYSTEM WIRING DIAGRAMS article in ELECTRICAL.
SYMPTOM INDEX
| Symptom | Perform Test |
|---|---|
| Malfunction Indicator Light Inoperative | A-1 |
| Malfunction Indicator Light Remains Illuminated | A-2 |
| Malfunction Indicator Light Inoperative With Ignition ON & Engine Does Not Start (ECM Power & Ground Circuit Check) | A-3 |
| Engine System Check | A-4 |