Code No.U0440: Implausible AWC data


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 - CAN Bus Diagnostics Table ).
  • If diagnosis code No.U0440 is set in ASC-ECU, always diagnose the CAN bus line. If there is any fault in the CAN bus lines, an incorrect diagnosis code may be set. In this case, the set diagnosis code is not highly reliable.
  • Before replacing the ECU, ensure that the communication circuit is normal.

OPERATION
S-AWC related signals are sent or received to and from between AWC-ECU and engine-ECU via CAN bus lines.

DIAGNOSIS CODE SET CONDITIONS
This diagnosis code is set when the S-AWC malfunction has been detected.

PROBABLE CAUSES

  • S-AWC system malfunction
  • Engine-ECU malfunction
  • ASC-ECU malfunction
  • External noise interference

DIAGNOSIS PROCEDURE

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

Q. 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 4.

STEP 2. Check whether the diagnosis code is set again.

Q. Is Code No.U0440 set?
Go to Step 3.
The procedure is complete.

STEP 3. M.U.T.-III other system diagnosis code
Use M.U.T.-III to check that other diagnosis code is set in the ECU corresponding to the relevant diagnosis.

Q. Is other diagnosis code set?
Troubleshoot for the relevant diagnosis code.
Go to Step 4.

STEP 4. Check whether the diagnosis code is set again.
Erase the diagnosis code.

Q. Is Code No.U0440 set?
Replace the hydraulic unit (integrated with ASC-ECU), and then go to Step 5.
Intermittent malfunction (Refer to GROUP 00 - How to Use Troubleshooting/How to Cope with Intermittent Malfunctions).

STEP 5. Check whether the diagnosis code is set again.
Erase the diagnosis code.

Q. Is Code No.U0440 set?
Return to Step 1.
This diagnosis is complete.