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DTC U1073: Bus-off
 
 
caution
  • If there is any problem in the CAN bus lines, an incorrect DTC may be set. Prior to this diagnosis, diagnose the CAN bus lines (Refer to GROUP 54C - CAN Bus Diagnostics Table ).
  • If DTC U1073 is set in ASC-ECU, always diagnose the CAN bus line. If there is any fault in the CAN bus lines, an incorrect DTC may be set. In this case, the set DTC is not highly reliable.
  • Whenever ECU is replaced, ensure that the CAN bus lines are normal.
 
 
DTC SET CONDITIONS
This DTC is set when ASC-ECU has ceased the CAN communication (bus off).
 
 
 
COMMENTS ON TROUBLE SYMPTOM
Malfunction of wiring harness, connector (s), or ASC-ECU may be present.
 
 
 
TROUBLESHOOTING HINTS
  • Wiring harness or connector failure of CAN bus line
  • ASC-ECU malfunction
  • Other ECU malfunction
 
 
 
 
DIAGNOSIS
STEP 1. Scan tool (M.U.T.-III) CAN bus diagnostics
(1)
cautionTo prevent damage to scan tool (M.U.T.-III), always turn the ignition switch to the "LOCK" (OFF) position before connecting or disconnecting scan tool (M.U.T.-III).
Connect scan tool (M.U.T.-III). Refer to "How to connect the Scan Tool (M.U.T.-III) ."
(2) Turn the ignition switch to the "ON" position.
(3) Diagnose the CAN bus line.
(4) Turn the ignition switch to the "LOCK" (OFF) position.
Is the check result normal?
Go to Step 2.
Repair the CAN bus lines (Refer to GROUP 54C - CAN Bus Diagnostics Table ). On completion, go to Step 3.
 
STEP 2. Check whether the DTC is set again.
Erase the DTC.
Is DTC U1073 set?
Replace the hydraulic unit (integrated with ASC-ECU) (Refer to ), and then 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 Use Troubleshooting/How to Cope with Intermittent Malfunctions ).
 
STEP 3. Check whether the DTC is set again.
Erase the DTC.
Is DTC U1073 set?
Return to Step 1.
This diagnosis is complete.