Code No. U0402: T/M (CAN message)


caution
  • If there is any problem in the CAN bus lines, an incorrect diagnosis code may be set. Prior to this diagnosis, diagnose the CAN bus lines (Refer to GROUP 54C - Troubleshooting ).
  • Whenever ECU is replaced, ensure that the CAN bus lines are normal.
  • When the hydraulic unit assembly (integrated with ASTC-ECU) is replaced, always carry out the calibration of the steering wheel sensor and the G sensor (Refer to ).

OPERATION


A/T-related signals are sent or received between the ASTC-ECU and the A/T-ECU via CAN bus lines.

DIAGNOSIS CODE SET CONDITIONS


This diagnosis code is set when the A/T-ECU malfunction has been detected.

PROBABLE CAUSES



DIAGNOSIS PROCEDURE

STEP 1. M.U.T.-III CAN bus diagnosis
Use the M.U.T.-III to diagnose the CAN bus lines.

Q. Is the check result normal?
Go to Step 3.
Repair the CAN bus lines (Refer to GROUP 54C - Troubleshooting ). On completion, go to Step 2.

STEP 2. Diagnosis code recheck after resetting CAN bus lines

Q. Is diagnosis code No. U0402 set?
Go to Step 3.
This diagnosis is complete.

STEP 3. Check for diagnosis codes of other systems.
Check if diagnosis code(s) other than U0402 is set.

Q. Is the diagnosis code set?
Follow the relevant diagnosis code procedure, and then go to Step 5.
Go to Step 4.

STEP 4. Use M.U.T.-III to confirm a diagnosis code of other systems.
Check if the diagnosis code is set in the A/T-ECU (Refer to GROUP 23A - Diagnosis Code Chart ).

Q. Is the diagnosis code set?
Troubleshoot the A/T-ECU diagnosis code. Then go to Step 5.
Go to Step 5.

STEP 5. Diagnosis code recheck
Check again if the diagnosis code is set.
(1)Erase the set diagnosis code.
(2)Ignition switch: "LOCK" (OFF)
(3)Ignition switch: "ON"

Q. Is diagnosis code No. U0402 set?
Replace the hydraulic unit assembly (integrated with ASTC-ECU) (Refer to ).
The trouble can be an intermittent malfunction (Refer to GROUP 00 - How to Cope with Intermittent Malfunction ).