Keyless Operation System (KOS)
DTC B1A28: Engine Control Module Authenticate ErrorCAUTION:
- When 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 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 CAN bus line
- Malfunction of KOS-ECU
- Malfunction of engine control module
- 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
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. Using scan tool MB991958, read the engine control module diagnostic trouble code.
Check again if the DTC is set to the engine control module.
Q: Is the DTC set?
YES : Troubleshoot the MFI system (Refer to Diagnostic trouble code chart). Diagnostic Trouble Code Descriptions
NO : Go to Step 3.
STEP 3. Using scan tool MB991958, read the diagnostic trouble code.
Check 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 DTC B1761 or B2206 set other than B1A28?
YES : Perform the troubleshooting for each DTC. Refer to Keyless Operation System (KOS) [B1761] and Keyless Operation System (KOS) [B2206].
NO : Go to Step 4.
STEP 4. 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. Then go to Step 5.
NO : The diagnosis is complete.
STEP 5. 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 the engine control module and record VIN.
NO : The procedure is complete.