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DTC B1A35: Transponder read error


caution
  • When DTC B1A35 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 B1A35 when it cannot receive data from the transponder.

TECHNICAL DESCRIPTION (COMMENT)


WCM determines that the abnormality is present, if it cannot receive the key ID for the ignition key when the ignition switch is turned ON.

TROUBLESHOOTING HINTS



DIAGNOSIS
Required Special Tools:
  • MB991958: Scan Tool (M.U.T.-III Sub Assembly)

    • MB991824: Vehicle 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.

(1)
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).
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?

Go to Step 2.

Repair the CAN bus line. (Refer to GROUP 54C, Diagnosis ).

STEP 2. Check the ignition key inserted in the key cylinder for interference.

Q. Are there other ignition keys or anything that interferes with the communication (things that generate radio waves such as magnets or air-cleaning device that has a power plug) near the ignition key inserted in the key cylinder?
Move away or remove other ignition keys or anything that interferes with the communication, and go to Step 3.
Go to Step 3.

STEP 3. Recheck for diagnostic trouble code.
Check again if the DTC is set to the WCM.
(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?
Go to Step 4.
The procedure is complete.

STEP 4. 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.

Q. Is the DTC set?
Go to Step 5.
Go to Step 6.

STEP 5. 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.

Q. Is the DTC set?
Go to Step 6.
The procedure is complete.

STEP 6. Replace the ignition key and recheck the diagnostic trouble code.
Replace the ignition key by which the DTC is set with a new one, register the key 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.

Q. Is the DTC set?
Replace WCM and register the ID codes (Refer to ).
The procedure is complete.