Keyless Operation System
DTC B1A28: Engine control module authenticate errorCAUTION:
- When the DTC B1A28 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
If the key certification result by KOS-ECU does not match with the engine control module status, KOS-ECU sets the DTC B1A28.
TECHNICAL DESCRIPTION (COMMENT)
KOS-ECU determines that the abnormality is present, if the key certification result and the engine control module status do not match after the engine start permission communication is completed.
TROUBLESHOOTING HINTS
- Malfunction of KOS-ECU
- Engine control module malfunction
- VIN registered in engine control module unmatched
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. Check the VIN registered in the engine control module and the vehicle's VIN.
Check if VIN registered in the engine control module matches with the vehicle's VIN.
Q: Do VIN registered in the engine control module and the vehicle's VIN match?
YES : Go to Step 3.
NO : Replace the engine control module and record the VIN. (Refer to General (Body and Chassis) - How To Perform Vehicle Identification Number (VIN) Writing.) After registering the VIN, go to Step 3.
STEP 3. Recheck for diagnostic trouble code.
Check again if the DTC is set to the KOS-ECU.
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 trouble can be an intermittent malfunction (Refer to General (Body and Chassis) - How to use Troubleshooting/inspection Service Points - How to Cope with Intermittent Malfunction).