Powertrain OBD System Check

IMPORTANT: Understanding and using the table correctly will reduce diagnostic time, and prevent the unnecessary replacement of parts.

After the visual/physical inspection is complete, the Powertrain On Board Diagnostic (OBD) System Check should be performed. The OBD System Check will provide direction to diagnose the following conditions.

- PCM inoperative or damaged
- No PCM data
- MIL inoperative
- PCM DTCs
- Fuel System Rich or Lean
- Customer Complaint Driveability Symptoms

The Powertrain On Board Diagnostic (OBD) System Check is designed as a Master table for driveability and emissions system diagnosis. The Powertrain On Board Diagnostic (OBD) System Check should always be used as the starting point for all Powertrain diagnosis.

The Powertrain On Board Diagnostic (OBD) System Check is an organized approach for identifying a problem. Driver Comments normally fall into one of the following areas:
- Steady SERVICE ENGINE SOON MIL
- Driveability problem
- Engine will not start or stalls after start