Code No.U1073: Bus-off


caution If the diagnosis code No. U1073 is output to the compressor & heater controller, be sure to carry out the CAN bus line diagnosis.
caution Before replacing ECU, ensure that the communication circuit is normal.

DIAGNOSIS CODE SET CONDITIONS


This code is set when the compressor & heater controller judges bus off.

PROBABLE CAUSES



DIAGNOSIS PROCEDURE

STEP 1. M.U.T.-III CAN bus diagnostics
Use the M.U.T.-III to diagnose the CAN bus lines.

Q. Is the check result normal?
Go to Step 2.
Repair the CAN bus lines. (Refer to GROUP 54C - Troubleshooting . ) After repairing the CAN bus lines, go to STEP 3.

STEP 2. Check whether the diagnosis code is reset.
Recheck if the diagnosis code is set.

  1. Erase the stored diagnosis code.
  2. Electric motor switch position: LOCK (OFF) → ON
  3. Check the diagnosis code.

Q. Is the diagnosis code set?
After replacing the compressor & heater controller, go to step 3.
If the trouble symptom is resolved, an intermittent malfunction such as poorly engaged connector(s) or wiring harness is suspected. (Refer to GROUP 00 - How to Cope with Intermittent Malfunction .)

STEP 3. Check whether the diagnosis code is reset.
Recheck if the diagnosis code is set.

  1. Erase the stored diagnosis code.
  2. Electric motor switch position: LOCK (OFF) → ON
  3. Check the diagnosis code.

Q. Is the diagnosis code set?
Return to Step 1.
The procedure is complete.




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