DTC U0100, U0129: Lost Communication with ECM/PCM "A"; Lost Communication with Brake System Control Module: Procedure

CHECK FOR DTC (CAN COMMUNICATION SYSTEM)
1. Clear the DTCs. Refer to DTC CHECK/CLEAR .
2. Check for DTCs. Refer to DTC CHECK/CLEAR .
  OK
  
  DTC is not output.
NG → See step 3

OK → See step 2
USE SIMULATION METHOD TO CHECK. Refer to HOW TO PROCEED WITH TROUBLESHOOTING
GO TO CAN COMMUNICATION SYSTEM (HOW TO PROCEED WITH TROUBLESHOOTING). Refer to HOW TO PROCEED WITH TROUBLESHOOTING