CODE No. U0101
T/M CAN timeout
caution |
- If diagnosis
code No. 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 earth circuit
and the communication circuit are normal.
|
OPERATION
The BSW-ECU (master) communicates with the A/T-ECU via the gateway-ECU and CAN
bus lines.
CHECK CONDITION
Ignition switch is in the ON position.
DIAGNOSTIC FUNCTION AND JUDGEMENT CRITERIA
If the BSW-ECU (master) cannot receive any signal from the A/T-ECU for at least
2.5 seconds, the ECU sets diagnosis code No. U0101.
PROBABLE CAUSES
- Power supply to the A/T-ECU fails
- Malfunction of the A/T-ECU
- Power supply to the gateway-ECU fails
- Malfunction of the gateway-ECU
- Malfunction of the BSW-ECU (master)
- Malfunction of the CAN bus
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 line (Refer to GROUP 54C - Troubleshooting
).
STEP 2. M.U.T.-III other system diagnosis code
Check that the other ECU performing CAN communication with A/T-ECU sets diagnosis
code No. U0101 [Refer to GROUP 54C - CAN Communication-related Diagnosis Code
(U-code) Table
].
Q.
Is the diagnosis code set?
Go to Step 3.
Go to Step 4.
STEP 3. Check whether the diagnosis code is set again.
Check again if the diagnosis code is set in the BSW-ECU (master).
|
(1)Erase the diagnosis code.
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(2)Turn the ignition switch from "LOCK" (OFF) position to "ON" position.
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(3)Check if diagnosis code is set.
|
Q.
Is the diagnosis code set?
Replace the A/T-ECU.
The trouble can be an intermittent malfunction such as a poor connection or open
circuit in the CAN bus lines between the A/T-ECU and the BSW-ECU (master) (GROUP 00 - How
to use Troubleshooting/inspection Service Points - How to Cope with Intermittent
Malfunction).
STEP 4. M.U.T.-III other system diagnosis code
Check if diagnosis code No. U0146 is set in the ETACS-ECU.
Q.
Is the diagnosis code set?
Troubleshoot the ETACS-ECU.
Go to Step 5.
STEP 5. M.U.T.-III other system diagnosis code
Check if diagnosis code No. U1073 is set in the gateway-ECU.
Q.
Is the diagnosis code set?
Troubleshoot the gateway-ECU (Refer to 54C - Troubleshoot <GATEWAY> - Diagnosis
Code Chart
).
Go to Step 6.
STEP 6. Check whether the diagnosis code is set again.
Check again if the diagnosis code is set in the BSW-ECU (master).
|
(1)Erase the diagnosis code.
|
|
(2)Turn the ignition switch from the LOCK (OFF) position to the ON position.
|
|
(3)Check if the diagnosis code is set.
|
Q.
Is the diagnosis code 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).