DTC U0100 (Flash Code 67) Lost Communication With ECM (AWR6B45)

1. DTC U0100 description

The TCM and ECM communicate control information via the CAN communication circuit. The TCM receives CAN messages from the ECM periodically. The TCM sets the DTC if CAN messages from the ECM are not received.

2. Condition for setting DTC U0100

Condition for running the DTC

  • The ignition switch is ON.
  • The battery voltage is 9.0 to 16.0 V.
  • The engine speed is 550 rpm or more.
  • The input speed is 550 rpm or more.
  • The output speed is 550 rpm or more.
  • DTC U0073 is not set.

Refer to "55.Transmission Control 5A.Troubleshooting(AWR6B45) DTC U0073 (Flash Code 65) Control Module Communication Bus Off".

Condition for setting the DTC

  • The TCM detects that CAN messages from the ECM cannot be received.

3. Action taken when DTC U0100 sets

  • The TCM flashes the check trans warning light. Refer to Action taken when DTC sets - Type A.

Refer to "55.Transmission Control 5A.Troubleshooting(AWR6B45) DTC type definitions".

  • The TCM fixes the engine speed to 4,500 rpm.
  • The TCM fixes the accelerator opening position to 50%.
  • The TCM fixes the engine torque to the maximum value.
  • The TCM fixes the engine coolant temperature to 80°C {176°F}.
  • The TCM fixes the wheel speed signal to 325 km {202 mph}.
  • The TCM inhibits the shift timing control.
  • The TCM inhibits the lock-up timing control.
  • The TCM inhibits the slip lock-up control.
  • The TCM inhibits the garage control.
  • The TCM inhibits the self-learning control.
  • The TCM inhibits the engine torque control.
  • The TCM inhibits the skip gear shift control.
  • If the DTC is set in the reverse gear, the current gear position is retained.
  • If the DTC is set while running, the current gear position is retained. If a solenoid malfunction is found while running in 6th gear, the gear is shifted to 5th.
  • When the vehicle is stopped, the gear is shifted to 3rd.

4. Condition for clearing DTC U0100

  • Refer to Condition for clearing the MIL, check trans warning light/DTC - Type A or Type B.

Refer to "55.Transmission Control 5A.Troubleshooting(AWR6B45) DTC type definitions".

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