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DTC U0440: Implausible AWC Data
 
 
caution
  • If there is any problem in the CAN bus lines, an incorrect DTC may be set. Prior to this diagnosis, diagnose the CAN bus lines (Refer to GROUP 54C - CAN Bus Diagnostics Table ).
  • If DTC U0440 is set in ASC-ECU, always diagnose the CAN bus line. If there is any fault in the CAN bus lines, an incorrect DTC may be set. In this case, the set DTC 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 ECM via CAN bus lines.
 
 
 
DTC SET CONDITIONS
This DTC is set when the S-AWC malfunction has been detected.
 
 
 
PROBABLE CAUSES
  • S-AWC system malfunction
  • ECM malfunction
  • ASC-ECU malfunction
  • External noise interference
 
 
 
 
DIAGNOSIS
STEP 1.Using scan tool (M.U.T.-IIISE), diagnose the CAN bus line.
(1)
cautionTo prevent damage to scan tool (M.U.T.-IIISE), always turn the ignition switch to the "LOCK" (OFF) position before connecting or disconnecting scan tool (M.U.T.-IIISE).
Connect scan tool (M.U.T.-IIISE). Refer to "How to connect the Scan Tool (M.U.T.-IIISE) ."
(2) Turn the ignition switch to the "ON" position.
(3) Diagnose the CAN bus line.
(4) Turn the ignition switch to the "LOCK" (OFF) position.
Is the check result normal?
Go to Step 2.
Repair the CAN bus lines (Refer to GROUP 54C - CAN Bus Diagnostics Table ).
 
STEP 2. Check whether the DTC is set again.
Is DTC U0440 set?
Go to Step 3.
The procedure is complete.
 
STEP 3. Using scan tool (M.U.T.-IIISE), check other system DTC.
Use scan tool (M.U.T.-IIISE) to check that other DTC is set in the ECU corresponding to the relevant diagnosis.
Is other DTC set?
Troubleshoot for the relevant DTC.
Go to Step 4.
 
STEP 4. Check whether the DTC is set again.
Erase the DTC.
Is DTC U0440 set?
Replace the hydraulic unit (integrated with ASC-ECU) (Refer to ).
Intermittent malfunction (Refer to GROUP 00 - How to Use Troubleshooting/How to Cope with Intermittent Malfunctions ).