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DTC U0168: KOS-ECU or WCM CAN Timeout
 
 
caution
  • If DTC U0168 is set in the occupant classification-ECU, always diagnose the CAN main bus lines.
  • When replacing the ECU, always check that the communication circuit is normal.
 
 
DIAGNOSTIC FUNCTION
If the signal from KOS-ECU or WCM cannot be received, the occupant classification-ECU sets the DTC U0168.
 
 
JUDGMENT CRITERIA
Because of the CAN-B bus circuit malfunction, if the occupant classification-ECU becomes unable to perform the normal data transmission, the occupant classification-ECU determines that an abnormality is present.
 
 
TROUBLESHOOTING HINTS
  • Malfunction of CAN bus line may be defective.
  • Malfunction of the KOS-ECU may be defective.
  • Malfunction of the WCM may be defective.
  • Malfunction of the occupant classification-ECU may be defective.
 
 
DIAGNOSIS
STEP 1. Using scan tool MB991958, diagnose the CAN bus line.
(1)
cautionTo prevent damage to scan tool MB991958, always turn the ignition switch to the "LOCK" (OFF) position before connecting or disconnecting scan tool MB991958.
Connect scan tool MB991958. Refer to "How to connect the Scan Tool (M.U.T.-III) ."
(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 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 MB991958, read the KOS-ECU or WCM diagnostic trouble code.
Check again if the DTC is set to the KOS-ECU or WCM.
Is the DTC set?
Diagnose the KOS or WCM. Then go to Step 4.
Go to Step 3.
 
STEP 3. Using scan tool MB991958, read diagnostic trouble code No. U0168 for other system.
Check if the DTC U0168 is set in ETACS-ECU, SRS-ECU, combination meter, A/C-ECU, CAN box unit, radio and CD player, satellite radio tuner, OSS-ECU.
Is the DTC set?
Replace the KOS -ECU (Refer to GROUP 42B, KOS-ECU ) or WCM (Refer to GROUP 42C, WCM)
Go to Step 4.
 
STEP 4. Recheck for diagnostic trouble code.
Check again if the DTC is set to the occupant classification-ECU.
(1) Erase the DTC.
(2) Turn the ignition switch from "LOCK" (OFF) position to "ON" position.
(3) Check if DTC is set.
(4) Turn the ignition switch to the "LOCK" (OFF) position.
Is the DTC set?
Replace the passenger seat cushion frame assembly (Refer to GROUP 52A, Front Seat Assembly ).
There is an intermittent malfunction such as poor engaged connector(s) or open circuit (Refer to GROUP 00, How to Cope with Intermittent Malfunction ).