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DTC U1109: ETACS CAN timeout
 
 
caution
  • If the DTC U1109 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 ETACS-ECU cannot be received, the occupant classification-ECU sets DTC U1109.
 
 
JUDGMENT CRITERIA
Because of the CAN-C bus circuit malfunction, if occupant classification-ECU becomes unable to perform the normal data transmission, occupant classification-ECU determines that an abnormality is present.
 
 
TROUBLESHOOTING HINTS
  • The CAN bus line may be defective
  • The ETACS-ECU may be defective
  • 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 ."
(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 ETACS-ECU diagnostic trouble code
Check again if the DTC is set in the ETACS-ECU.
Is the DTC set?
Diagnose the ETACS-ECU. Then go to Step 4.
Go to Step 3.
 
STEP 3. Using scan tool MB991958, read diagnostic trouble code No. U1109 for other system.
Check if DTC U1109 set in SRS-ECU, combination meter, A/C-ECU.
Is the DTC set?
Replace the ETACS-ECU (Refer to GROUP 54A, ETACS - ETACS-ECU ).
Go to Step 4.
 
STEP 4. Recheck for diagnostic trouble code.
Check again if the DTC is set in 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 front seat cushion cover and pad 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 ).