Radio and CD Player

DTC U0019: Bus off (CAN-B)

CAUTION:

- If DTC U0019 is set, be sure to diagnose the CAN bus line.
- When replacing the radio and CD player, always check that the communication circuit is normal.

TROUBLE JUDGMENT

When the radio and CD player is returned from the bus off state, or when the bus error is indicated to the radio and CD player state, the DTC U0019 (CAN-B) is set.

COMMENTS ON TROUBLE SYMPTOM

The radio and CD player, power supply for the radio and CD player, ground circuit, or CAN bus line may have a problem.

PROBABLE CAUSES

- Malfunctions of radio and CD player
- Malfunction of CAN bus line wiring harness and connector

DIAGNOSIS

Required Special Tools:

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

STEP 1. Using scan tool MB991958, diagnose the CAN bus line.

Use scan tool MB991958 to diagnose the CAN bus lines.





(1)
CAUTION:
To 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) Scan Tool Testing and Procedures."
(2)Turn the ignition switch to "ON" position.
(3)Diagnose the CAN bus line.

Q. Is the check result normal?

YES Go to Step 2.

NO Repair the CAN bus line. CAN Bus Diagnostics Chart.) On completion, go to Step 2.

STEP 2. Check whether the scan tool MB991958 can communicate with the radio and CD player.

Q. Is the check result normal?

YES Erase the diagnostic trouble code. The procedure is complete.
NO Check the power supply circuit of the radio and CD player, and repair if necessary.