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DTC U0019: Bus Off (CAN-B)
 
 
caution
  • If the DTC U0019 is set, be sure to diagnose the CAN main bus line.
  • When replacing the ECU, always check that the communication circuit is normal.
 
 
DIAGNOSTIC FUNCTION
If the CAN-B circuit malfunction occurs, the SRS-ECU sets the DTC U0019.
 
 
JUDGMENT CRITERIA
Because of the CAN-B bus circuit malfunction, if SRS-ECU becomes unable to perform the normal data transmission, SRS-ECU determines that an abnormality is present.
 
 
TROUBLESHOOTING HINTS
The CAN bus line may be defective
 
 
DIAGNOSIS
STEP 1. Using scan tool MB991958, diagnose the CAN bus line.
(1) Turn the ignition switch from "LOCK" (OFF) position to "ON" position.
(2) Diagnose the CAN bus line.
(3) 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. Recheck for diagnostic trouble code.
Check again if the DTC is set to the SRS-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 SRS-ECU (Refer to ).
There is an intermittent malfunction such as poor engaged connector(s) or open circuit (Refer to GROUP 00, How to Cope with Intermittent Malfunction ).