WagonRFix

U0100 on Suzuki Wagon R: Lost Communication With ECM/PCM A

Short answer: U0100 means “Lost Communication With ECM/PCM A”. The car’s computer has found a fault in the Network system and turns on the Check engine light (MIL). First check: check battery voltage and the main fuses.

Standard OBD-II code Same meaning on all cars (SAE J2012). Not checked against this car’s factory manual.

Code
U0100
System
Network
Dashboard light
Check engine light (MIL)
Also sold as
Maruti Suzuki Wagon R, Suzuki Karimun Wagon R (Indonesia)
Applies to
Generic OBD-II meaning. Not every code is used by this car.
Confidence
medium (generic OBD-II definition, not checked against the factory manual for this car)
Source
obd-codes.com

Symptoms and when it is set

  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…

Likely 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, in order

  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

Related on this car

Same code on other cars

← P2238 U0101 →

Clearing the code does not fix the fault. If it comes back, the problem is still there. For brakes, airbags and steering, see a trained mechanic.