Code No.U1073: Bus-Off
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- If diagnosis code No.U1073 is set in the meter-ECU, diagnose the CAN bus lines.
- Whenever the ECU is replaced, ensure that the communication circuit is normal.
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TROUBLE JUDGMENT
If the combination meter ceases communicating once (i.e. bus off). Immediately after the combination meter returns to communication, the diagnosis code is set.
COMMENTS ON TROUBLE SYMPTOM
The wiring harness wire or connectors may have loose, corroded, or damage terminals, or terminals pushed back in the connector, or the combination meter may be defective.
PROBABLE CAUSES
- Damaged harness wires and connectors
- Malfunction of the combination meter
DIAGNOSIS PROCEDURE
STEP 1. M.U.T.-III CAN bus diagnostics
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Since the radiator fan rotates during CAN bus line diagnostics, make sure that no one is servicing the engine compartment before diagnosing the CAN bus line. Since the CAN communication stops when diagnosing the CAN bus line, the ETACS-ECU detects the time-out of the engine-ECU, and activates the radiator fan to prevent overheating as fail-safe.
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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 line (Refer to GROUP 54C, Troubleshooting 
). Repair the CAN bus line and go to Step 3.
STEP 2. Check whether the diagnosis code is reset
Recheck if the diagnosis code is set.
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(1)Erase the diagnosis code.
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(2)Turn the ignition switch to "ON" position.
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(3)Check if the diagnosis code is set.
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Q.
Is the diagnosis code set?
After the combination meter is replaced, then perform the variant coding (Refer to GROUP 00, Precautions Before Service - How to Perform Variant Coding ). Then go to Step 3.
If the trouble is solved, it is determined that there is an intermittent malfunction such as poor engaged connector(s) or open circuit (Refer to GROUP 00, How to Use Troubleshooting/Inspection Service Points - How to Cope with Intermittent Malfunctions ).
STEP 3. Check whether the diagnosis code is reset.
Recheck if the diagnosis code is set.
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(1)Erase the diagnosis code.
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(2)Turn the ignition switch to "ON" position.
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(3)Check if the diagnosis code is set.
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Q.
Is the diagnosis code set?
Go to Step 1.
The procedure is complete.