DTC U1040: Loss Of Communication With TCS: Testing

If IPC diagnostic system check was performed, go to next step. If IPC diagnostic system check was not performed, go to procedures in IPC DIAGNOSTIC SYSTEM CHECK .
Turn ignition off. Connect scan tool. Turn ignition on. Using scan tool, attempt to establish communication with TCS. If communication can be established, go to next step. If communication cannot be established, see ANTI-LOCK BRAKE SYSTEM article in BRAKES section.
Using scan tool, select IPC DTCs function. Check for DTC U1255. If DTC U1255 exists, go to DTC U1255: SERIAL DATA LINE MALFUNCTION . If DTC U1255 does not exist, go to next step.
Check serial data line for following intermittent conditions:
- An open in serial data line between IPC and TCS.
- Short to ground.
- Short to voltage.
- Check star connector No. 1 (ensure bus bar is properly inserted).
- Loose or damaged terminals.
If no problem is found, go to next step. If problem is found, repair as necessary. Go to step 6).
Turn ignition off. Reinstall all components and connectors. Turn ignition on. Clear DTCs. Check for DTCs. If DTC U1040 is current, see ANTI-LOCK BRAKE SYSTEM article in BRAKES section. If DTC U1040 is not current, system is operating properly.
Turn ignition off. Reinstall all components and reconnect all connectors. Turn ignition on. Clear DTCs. Perform procedures in IPC DIAGNOSTIC SYSTEM CHECK .