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DTC U0101 T/M CAN timeout
 
 
caution
  • If DTC U0101 is set in the BSW-ECU (master), always diagnose the CAN bus line.
  • Before replacing the ECU, ensure that the power supply circuit, the ground circuit and the communication circuit are normal.
 
 
OPERATION
The BSW-ECU (master) communicates with the TCM via the gateway-ECU and CAN bus lines.
 
 
CHECK CONDITION
Ignition switch is in the ON position.
 
 
DIAGNOSTIC FUNCTION AND JUDGMENT CRITERIA
If the BSW-ECU (master) cannot receive any signal from the TCM for at least 2.5 seconds, the ECU sets DTC U0101.
 
 
TROUBLESHOOTING HINTS
  • Power supply to the TCM
  • The TCM may be defective
  • Power supply to the gateway-ECU fails
  • The gateway-ECU may be defective
  • The BSW-ECU (master) may be defective
  • The CAN bus may be defective
 
 
DIAGNOSIS
STEP 1. Using scan tool (M.U.T.-III) CAN bus diagnostics
Use the scan tool (M.U.T.-III) to diagnose the CAN bus lines.
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) ."
Is the check result normal?
Go to Step 2.
Repair the CAN bus line (Refer to GROUP 54C - Troubleshooting ).
 
STEP 2. Using scan tool (M.U.T.-III) other system DTC
Check that the other ECU performing CAN communication with TCM sets DTC U0101 [Refer to GROUP 54C - CAN Communication-related Diagnostic trouble Code (U-code) Table ].
Is the DTC set?
Go to Step 3.
Go to Step 4.
 
STEP 3. Check whether the DTC is set again.
Check again if the DTC is set in the BSW-ECU (master).
(1) Erase the DTC.
(2) Turn the ignition switch from "LOCK" (OFF) position to "ON" position.
(3) Check if DTC is set.
Is the DTC set?
Replace the TCM.
The trouble can be an intermittent malfunction such as a poor connection or open circuit in the CAN bus lines between the TCM and the BSW-ECU (master) (Refer to GROUP 00 - How to use Troubleshooting/inspection Service Points - How to Cope with Intermittent Malfunction ).
 
STEP 4. Using scan tool (M.U.T.-III) other system DTC
Check if DTC U0147 is set in the ETACS-ECU.
Is the DTC set?
Troubleshoot the ETACS-ECU (Refer to ).
Go to Step 5.
 
STEP 5. Using scan tool (M.U.T.-III) other system DTC
Check if DTC U1073 is set in the gateway-ECU.
Is the DTC set?
Troubleshoot the gateway-ECU (Refer to GROUP 54C - Troubleshoot <GATEWAY> - Diagnostic trouble Code Chart ).
Go to Step 6.
 
STEP 6. Check whether the DTC is set again.
Check again if the DTC is set in the BSW-ECU (master).
(1) Erase the DTC.
(2) Turn the ignition switch from the "LOCK" (OFF) position to the "ON" position.
(3) Check if the DTC is set.
Is the DTC set?
Replace the BSW-ECU (master).
Intermittent malfunction is suspected (Refer to GROUP 00 - How to Use Troubleshooting/Inspection Service Points - How to Cope with Intermittent Malfunction ).