Tests AH: DTC U0100 - Lost Communication With ECM/PCM

PINPOINT TEST AH: DTC U0100 - LOST COMMUNICATION WITH ECM/PCM

AH1-AH4:

AH5:

Normal Operation
The instrument cluster sets DTC U0100 if data messages for following systems or data types are missing:
- Passive anti-theft system (PATS)
- Speed control
- Accelerator pedal position
- Transmission type
- Engine coolant temperature
- Odometer rolling count
- Fuel flow
- Malfunction indicator lamp (MIL)
- Fail safe cooling mode
- Electronic throttle control
- Charging system
- Check fuel cap
- AC clutch engaged
- Engine rpm
- Vehicle identification number (VIN)

Once the instrument cluster sets DTC U0100, multiple gauges or indicators are likely to be inoperative in the cluster. Other modules that require data from the instrument cluster all set communication DTCs and may also exhibit system function concerns.

Possible Causes
- Low battery voltage
- Communication network
- PCM