U0100 – Lost Communication With ECM/PCM A

System: Network
Dashboard light: Check engine light (MIL)
Check-engine blink code: —
Applies to: Generic OBD-II meaning. Not every code is used by this car.
Description: Lost Communication With ECM/PCM A
Detection / symptoms: 1.Check engine light on 2.Vehicle stalls and will not crank or restart 3.Vehicle may start after sitting idle for a period of time, however, it would be risky to operate because it could fail again at a most inopportune…
Possible causes: 1.This is not a common problem. It's been my experience that the most likely failure is the ECM, PCM or transmission control module. There are at… 2.A communications failure between anything in the network will cause this code. If additional codes are present to isolate the problem, diagnosis… 3.The installation of performance enhancing computer chips or devices may not be compatible with the ECM or CAN bus wiring causing the lost… 4.A bent or pushed out pin terminal in one of the connectors or a loose ground to the computer will cause such a code. Jumping a dead battery and…
What to check: 1.Check battery voltage and the main fuses 2.Check the connectors of the module named in the code 3.Read codes from all modules with a capable scanner
Confidence: medium (generic OBD-II definition, not checked against the factory manual for this car)

Generic OBD-II meaning (obd-codes.com), not checked against this car's factory manual. Clear the code and test-drive to confirm it returns. Search all fault codes · Common problems · Warning lights