B1A30

Code

Generic B — Body

Immobilizer: Transponder Key Not Recognized

Brand: Generic

Type: B — Body

Views: UK: 12 EN: 33 RU: 16

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Page language: EN

Damaged or unprogrammed transponder key
Faulty or weak transponder battery (if smart key)
Faulty immobilizer antenna/read coil (around the ignition cylinder or key reader)
Faulty immobilizer control module (BCM/ICM) or firmware error
Wiring or connector faults between antenna, module and BCM
Poor grounding or low vehicle battery voltage during key read

Transponder ID readback — Expected: valid programmed key ID string; Fault: no read or unknown ID
Antenna coil supply voltage — Typical: ~5 V or battery supply depending on design; Fault: open/low
Antenna coil resistance — Typical: manufacturer spec (check service manual); Fault: open/short
Immobilizer module wake/logic supply — Typical: battery voltage when key present; Fault: no power
CAN/BUS immobilizer messages — Expected: key status and authorization flags; Fault: missing or error frames
Vehicle battery voltage during read — Expected >= 12.2 V; Fault: low voltage may cause read failure

Retrieve code(s) and freeze frame data with a capable scan tool. Note which key was used and any network errors.
Attempt start with a known-good/spare programmed key. If spare works, suspect failed key (replace/reprogram key).
Check vehicle battery voltage and charging; recharge or replace battery if low and clear codes, then retest.
Visually inspect ignition area antenna/read coil, connectors and wiring for damage, corrosion or looseness. Wiggle test connectors while observing scan tool key-read data.
Measure antenna coil resistance and supply voltage per service manual. Replace coil/reader if out of spec.
Check immobilizer/BCM for power, grounds and CAN communication. Repair wiring or connectors that show faults.
Use dealer-level or manufacturer-approved diagnostic tool to read transponder ID, re-learn keys or view immobilizer module internal status. Follow OEM reprogramming procedure if keys are missing.
If antenna, wiring and keys are good but module reports faults or cannot learn keys, evaluate/replace immobilizer control module/BCM per service info and reprogram as required.
After repairs or key programming, clear DTCs and perform multiple start cycles with each key to confirm repeatable recognition.
If intermittent and no fault found, inspect for RF interference sources or recently installed aftermarket devices and remove/test.