Keyless Operation System (KOS)

DTC B2401: Keyless/KOS key ID not registered

CAUTION:
- If DTC B2401 is set, be sure to diagnose the CAN bus line.
- When replacing the ECU, always check that the communication circuit is normal.

DIAGNOSTIC FUNCTION
If no keyless operation key ID is registered with KOS-ECU or if the keyless operation key with ID not registered is used, KOS-ECU sets DTC B2401.

JUDGMENT CRITERIA
If the number of the registered keyless operation keys is 0, or the registration of a keyless operation key fails when the number of the registered keyless operation keys is 0, it is judged as abnormal.

PROBABLE CAUSES
- Malfunction of CAN bus line
- The registration of a keyless operation key ID fails when no keyless operation key ID is registered.
- Malfunction of the keyless operation key
- 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 busline.






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 (Refer to Controller Area Network (CAN), Diagnosis).

STEP 2. Register the keyless operation key ID and recheck the diagnostic trouble code.

Register the keyless operation key ID, and check whether the DTC is reset. (Refer to ID Code Registration Necessity Judgment Table)

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 a new one, register the key ID and keyless operation key ID (Refer to ID Code Registration Necessity Judgment 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 Code Registration Necessity Judgment Table)

NO: The procedure is complete.