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DTC B1A25: Key ID unmatched
 
 
cautionWhen 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
WCM sets DTC B1A25 when the received key ID is different from the one registered in it.
 
 
TECHNICAL DESCRIPTION (COMMENT)
WCM determines that the abnormality is present, if the key ID for the ignition key does not match the one registered in WCM when the ignition switch is turned ON.
 
 
TROUBLESHOOTING HINTS
  • Malfunction of the ignition key
  • Accessory key not registered
  • Accessory WCM not registered
  • Key is registered to another vehicle
  • Malfunction of WCM
 
 
DIAGNOSIS
STEP 1. Using scan tool MB991958, diagnose the CAN bus line.
(1)
cautionTo 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. Refer to "How to connect the Scan Tool (M.U.T.-III) ."
(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.
Is the CAN bus line found to be normal?
Go to Step 2.
Repair the CAN bus line (Refer to GROUP 54C, Diagnosis ).
 
STEP 2. Register the key ID and recheck the diagnostic trouble code.
Register the key ID of the ignition key (refer to ), 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.
Is the DTC set?
Go to Step 3.
The procedure is complete.
 
STEP 3. Replace the ignition key and recheck the diagnostic trouble code.
Replace the ignition key by which the DTC is set with the other key, 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.
Is the DTC set?
Go to Step 4.
Go to Step 5.
 
STEP 4. Register the key ID and recheck the diagnostic trouble code.
Register the key ID of the ignition key (refer to ), 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.
Is the DTC set?
Go to Step 5.
The procedure is complete.
 
STEP 5. Replace the ignition key and recheck the diagnostic trouble code.
Replace the ignition key with a new one, register the key ID and keyless ID of the new key, (refer to ), 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.
Is the DTC set?
Replace WCM and register the ID codes (Refer to ).
The procedure is complete.