B1C39

Code

LAND ROVER B — Body

Key

Brand: LAND ROVER

Type: B — Body

Views: UK: 18 EN: 27 RU: 19

AI status

Completed

ready

Completed 100%

Page language: EN

Causes

Key transponder damaged or missing
Key fob battery low or dead
Key not programmed or lost programming
Immobiliser/BCM (body control module) antenna or wiring fault
Connector corrosion or poor grounding at key reader or module
Software or module communication error between modules (BCM/PKM/ECU)

Symptoms

Engine will not start or crank due to immobiliser preventing start
Security/immobiliser warning lamp or message in instrument cluster
Remote locking/unlocking or panic functions intermittent or not working
‘Key not recognised’ or ‘Key faulty’ message displayed
Intermittent starting problems that resolve when using a different key

What to check

Check owner manual messages and warning lamps for key/immobiliser alerts
Attempt to start using a known-good spare key
Check and replace key fob battery, verify contacts and remote buttons operate
Read all stored DTCs from body/immobiliser/engine modules with appropriate diagnostic tool
Inspect key for physical or water damage
Inspect antenna/read coil, connectors and wiring for corrosion, damage, or poor ground

Signal parameters

Immobiliser LF transponder field typically ~125 kHz (wake/read coil)
Key fob RF transmit frequency typical 315/433 MHz (region dependent)
Key reader/antenna coil resistance — compare to manufacturer specification (typical coil resistances vary by model)
Connector voltages: 12 V supply to immobiliser/key module and proper ground
CAN/LIN bus communication between BCM and engine/immobiliser module (normal message traffic expected)

Diagnostic algorithm

Confirm symptom and record exact instrument cluster messages and conditions when fault occurs
Try a spare programmed key. If spare works, suspect primary key transponder or key internal fault
Replace or test key fob battery and retest remote functions
Use a compatible diagnostic tool to read and record all related DTCs from body/immobiliser and engine modules
Inspect and test immobiliser antenna/read coil resistance and continuity; compare to factory spec
Inspect wiring and connector pins for corrosion, bent pins or poor mating; repair as required
Verify power and ground at key reader/immobiliser module and check module communications on CAN/LIN network
If antenna and wiring are OK, attempt reprogramming/relearning of key(s) per manufacturer procedure
Clear codes and retest vehicle multiple cycles (lock/unlock, start)
If problem persists after keys and wiring verified, consider module fault — consult manufacturer guidance for module replacement or software update; follow security and programming procedures to program new module/keys

Likely causes

Weak/dead key fob battery or poor key battery contact
Unprogrammed or corrupt key transponder
Damaged key (physical or water damage)
Faulty immobiliser antenna/read coil or bad wiring/connectors

Fault status

⚠️ Status

Key/transponder recognition fault — vehicle may not start and remote/key functions may be disabled until key and immobiliser issue is resolved.

🟡 Repair difficulty: Medium

⏱️ Diagnostic time: 0.5-3.0 hours

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Repair manuals

Manual library for LAND ROVER

160

Browse 160 LAND ROVER manuals: repair procedures, diagnostics, wiring diagrams, component locations, service data and Labor Times by year, model and trim.

LAND ROVER

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