Keyless Operation System (KOS)

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

KOS-ECU sets DTC B1A25 when the received key ID is different from the one registered in it.

TECHNICAL DESCRIPTION (COMMENT)

KOS-ECU determines that the abnormality is present, if the key ID does not match the one registered in it when the ignition switch is turned ON.

TROUBLESHOOTING HINTS

- Malfunction of the keyless operation key
- Accessory key not registered
- Accessory KOS-ECU not registered
- Key is registered to another vehicle
- Malfunction of KOS-ECU

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

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 and keyless operation key ID of the keyless operation key by which the DTC is set (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 keyless operation key and recheck the diagnostic trouble code.

Replace the keyless operation key for which the DTC is set with the other key, and check whether the DTC is reset.

(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 and keyless operation key ID of the keyless operation key by which the DTC is set (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 keyless operation key and recheck the diagnostic trouble code.

Replace the keyless operation key for which the DTC is set with a new one, register the key ID and keyless operation key ID (Refer to ID registration procedure manual - ID codes registration judgement table), and check whether the DTC is reset.

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