Wireless Control Module (WCM)

DTC B1A25: Key ID unmatched

CAUTION:
When the DTC B1A25 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 B1A25 when the received key ID is different from the one registered in it.

TECHNICAL DESCRIPTION (COMMENT)

WCM determines that the abnormality is present, if the key ID for the ignition key does not match the one registered in WCM when the ignition switch is turned ON.

TROUBLESHOOTING HINTS

- Malfunction of CAN bus line
- Malfunction of the ignition key
- Accessory key not registered
- Accessory WCM not registered
- Key is registered to another vehicle
- 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 Go to Step 3.
NO The procedure is complete.
STEP 3. Replace the ignition key and recheck the diagnostic trouble code.

Replace the ignition key by which the DTC is set with the other key, 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 Go to Step 4.
NO Go to Step 5.
STEP 4. 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 Go to Step 5.
NO The procedure is complete.
STEP 5. Replace the ignition key and recheck the diagnostic trouble code.

Replace the ignition key with a new one, register the key ID and keyless ID of the new 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.