Wireless Control Module (WCM)

DTC B1A24: Key ID not registered

CAUTION:

- When the DTC B1A24 is set, be sure to diagnose the CAN bus line.
- When replacing the ECU, always check that the communication circuit is normal.

DTC SET CONDITION

WCM sets DTC B1A24 when the key ID was not registered in it.

TECHNICAL DESCRIPTION (COMMENT)

WCM determines that the abnormality is present, if the ignition key's key ID is not registered in WCM when the ignition switch is turned ON.

TROUBLESHOOTING HINTS

- Malfunction of CAN bus line
- Key ID not registered
- Malfunction of the ignition key
- Malfunction of WCM

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.





(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 to the data link connector.
(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.

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. Register the key ID and recheck the diagnostic trouble code.

Register the key ID of the ignition key (Refer to ID registration procedure manual - ID codes registration judgement table), and recheck if the DTC is set.

(1)Turn the ignition switch from the "LOCK" (OFF) position to the "ON" position.

(2)Check if the DTC is set.

Q. Is the DTC set?

YES Replace WCM and register the ID codes (Refer to ID registration procedure manual - ID codes registration judgement table).
NO The procedure is complete.