Keyless Operation System

DTC B1A25: Key ID unmatched

DTC SET CONDITION
KOS-ECU sets the 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 transponder ID does not match the one registered in it when the ignition switch is turned ON.

TROUBLESHOOTING HINTS
- Malfunction of the emergency 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 (Vehicles with CAN communication system)

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






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).

1. 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.

STEP 2. Register the key ID and recheck the diagnostic trouble code.
Register the key ID of the emergency key by which the DTC is set 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 emergency key and recheck the diagnostic trouble code.
Replace the emergency key for which the DTC is set with a new one, register the key ID and keyless operation key ID 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.

NO : The procedure is complete.