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DTC U0101: T/M CAN timeout
 
 
caution
  • If DTC U0101 is stored, be sure to diagnose the CAN bus line.
  • Before replacing ECU, ensure that the communication circuit is normal.
 
 
DTC SET CONDITION
When the signal from the CVT-ECU cannot be received, KOS-ECU stores DTC U0101.
 
 
TECHNICAL DESCRIPTION (COMMENT)
Check Conditions
  • When all the following conditions are met.
    1. Power supply mode: ON
    2. ETACS-ECU system voltage is at 10 to 16 V.
Judgment Criterion
  • After the following condition is met, 2,500 ms or more have elapsed.
    1. CAN signal from the CVT-ECU cannot be received.
 
 
TROUBLESHOOTING HINTS
  • Malfunction of the CAN bus line
  • CVT-ECU malfunction
  • Malfunction of KOS-ECU
 
 
DIAGNOSIS
STEP 1. Using scan tool (M.U.T-III), diagnose the CAN bus line.
(1)
cautionTo prevent damage to scan tool (M.U.T-III), always turn the power supply mode of the engine switch to the 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 power supply mode of the engine switch to ON.
(3) Diagnose the CAN bus line.
(4) Turn the power supply mode of the engine switch to OFF.
Is the CAN bus line found to be normal?
Go to Step 2.
Repair the CAN bus line (Refer to GROUP 54C, Diagnosis ).
 
STEP 2. Using scan tool (M.U.T-III), read the other system diagnostic trouble code.
Check if DTC is stored in the CVT-ECU.
(1)
cautionTo prevent damage to scan tool (M.U.T-III), always turn the power supply mode of the engine switch to the OFF position before connecting or disconnecting scan tool (M.U.T-III).
Connect scan tool (M.U.T-III). Refer to "How to connect scan tool (M.U.T.-III) ."
(2) Erase the DTC.
(3) Turn the power supply mode of the engine switch to ON.
(4) Check if DTC is stored.
(5) Turn the power supply mode of the engine switch to OFF.
Is the DTC stored?
Diagnose the CVT-ECU (Refer to GROUP 23A, Troubleshooting ). Then go to Step 3.
Go to Step 3.
 
STEP 3. Using scan tool (M.U.T-III), read the other system diagnostic trouble code.
(1)
cautionTo prevent damage to scan tool (M.U.T-III), always turn the power supply mode of the engine switch to the OFF position before connecting or disconnecting scan tool (M.U.T-III).
Connect scan tool (M.U.T-III). Refer to "How to connect scan tool (M.U.T.-III) ."
(2) Turn the power supply mode of the engine switch to ON.
(3) Check if DTC U0101 is stored in the ETACS-ECU.
(4) Turn the power supply mode of the engine switch to OFF.
Is the DTC stored?
Go to Step 4.
Go to Step 5.
 
STEP 4. Recheck for diagnostic trouble code.
Check again if the DTC is stored in the KOS-ECU.
(1) Erase the DTC.
(2) Turn the power supply mode of the engine switch from OFF to ON.
(3) Check if DTC is stored.
(4) Turn the power supply mode of the engine switch from ON to OFF.
Is the DTC stored?
Replace the CVT-ECU.
A poor connection, open circuit or other intermittent malfunction is present in the CAN bus lines between the CVT-ECU and the KOS-ECU (Refer to GROUP 00, How to Use Troubleshooting/Inspection Service Points - How to Cope with Intermittent Malfunctions ).
 
STEP 5. Recheck for diagnostic trouble code.
Check again if the DTC is stored in the KOS-ECU.
(1) Erase the DTC.
(2) Turn the power supply mode of the engine switch from OFF to ON.
(3) Check if DTC is stored.
(4) Turn the power supply mode of the engine switch from ON to OFF.
Is the DTC stored?
Replace the KOS-ECU and register the ID codes (Refer to ).
A poor connection, open circuit or other intermittent malfunction is present in the CAN bus lines between the CVT-ECU and the KOS-ECU (Refer to GROUP 00, How to Use Troubleshooting/Inspection Service Points - How to Cope with Intermittent Malfunctions ).