Pcm UART Data Line
- Ensure there is proper connection between scan tool and DLC, and there are no loose or missing DLC terminals.
- If all modules are not accessible with a scan tool, check for an open in circuit 800 between DLC terminal No. 9 and splice S248.
- If a single module is not accessible with a scan tool, check for an open in circuit 800 between splice S248 and the component.
- Visually inspect for obvious signs of mechanical and electrical damage. Inspect for blown fuses and damaged relays. Inspect for loose or corroded connections, damaged wiring harnesses and/or switches. Check for a broken or partially broken wire inside insulation, which could cause system malfunction but prove good in a continuity/voltage check with system disconnected. These circuits may be intermittent or resistive when loaded and should be checked by monitoring the voltage drop with the system under load.
- Ensure any aftermarket electronic equipment is properly installed. If fault is found, repair as necessary. If no fault is found, go to UART DATA LINE DIAGNOSIS under SYSTEM TESTS.