Troubleshooting Hints

The most likely causes are:

• No power supply to ECM (M/T) or PCM (A/T).
• Defective ground circuit of ECM (M/T) or PCM (A/T).
• Improper communication line between ECM (M/T) or PCM (A/T) and scan tool.
• Open circuit between ECM (M/T) or PCM (A/T) and data link connector.
• Defective ECM (M/T) or PCM (A/T).
• Malfunction of ECM (M/T) or PCM (A/T) power supply circuit.
• Malfunction of the ECM (M/T) or PCM (A/T).