Supplemental Restraint System (SRS)

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.

DTC SET CONDITION

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

Required Special Tools:

- MB991958: Scan Tool (M.U.T.-III Sub Assembly)
- MB991824: Vehicles Communication Interface (V.C.I.)
- MB991827: M.U.T.-III USB Cable
- MB991910: M.U.T.-III Main Harness A (Vehicles with CAN communication system)

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.

Q. Is the CAN bus line found to be normal?

YES Go to Step 2.
NO Repair the CAN bus line CAN Bus Diagnostics Chart).
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.

Q. Is the DTC set?

YES Replace the SRS-ECU (Refer to Service and Repair).
NO There is an intermittent malfunction such as poor engaged connector(s) or open circuit How to Cope With Intermittent Malfunctions).