DTC U0100[00] Lost Communication With ECM (Auto A/C)

1. DTC U0100[00] description

The auto A/C control unit and ECM communicate information with each other using the CAN bus. The auto A/C control unit determines whether CAN messages are constantly flowing from the ECM. If the auto A/C control unit cannot receive the CAN messages from the ECM, the DTC is set.

2. Condition for setting DTC U0100[00]

Condition for running the DTC

  • DTC U0064[88] is not set.

Refer to "57.HVAC Control 7A.Troubleshooting(Auto A/C) DTC U0064[88] CAN Network: Bus-Off (CAN)".

Also, the following are met for 5 seconds or more:

  • The ignition switch is ON.
  • The ignition voltage is 10 V or more.

Condition for setting the DTC

  • The automatic A/C control unit detects that the CAN messages cannot be received from the ECM.

3. Action taken when DTC U0100[00] sets

  • The auto A/C control unit sets the signal input from the ECM to the default value.
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