B2399

Code

LAND ROVER B — Body

Body Control Module (BCM) — Internal Fault

Brand: LAND ROVER

Type: B — Body

Views: UK: 16 EN: 24 RU: 17

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Page language: EN

Causes

BCM internal hardware failure (processor, memory, solder joint)
Corrupted BCM firmware or software
Intermittent or low vehicle battery/voltage supply to BCM
Poor ground or power connections to BCM
Water intrusion or physical damage to BCM
ECU communication errors (CAN/LIN bus interruptions)

Symptoms

One or more body electrical functions inoperative or intermittent (locks, lights, wipers, windows)
Multiple unrelated body modules showing errors or not responding
Warning lamps illuminated or message center warnings for electrical faults
Vehicle does not enter/exit sleep or has excessive wake events
Stored communication faults for CAN/LIN networks

What to check

Read all stored and pending fault codes from all modules (scan tool) and note freeze frame data
Check battery state of charge and measure resting voltage (should be ~12.6 V) and cranking voltage under load
Inspect BCM connector(s) for corrosion, bent pins, moisture, or damage and ensure secure fit
Verify BCM power and ground circuits for correct voltage and continuity
Check CAN/LIN bus integrity: resistance, short-to-power/ground, and proper termination
Confirm recent service history for battery replacement, jump-starts, or ECU reflash/programming

Signal parameters

Battery supply voltage to BCM (key off and key on) — expect ~12.4–12.8 V resting, ~13.5–14.5 V running
Ground circuit continuity (
CAN bus voltages: CAN_H ~2.5–3.5 V idle, CAN_L ~1.5–2.5 V idle; differential ~2.5 V
LIN bus idle voltage ~12 V or specified system level depending on design
Wake/sleep request signals and BCM internal watchdog status (as reported by scan tool)
Module alive/heartbeat messages presence and frequency on network

Diagnostic algorithm

Retrieve full DTC list and freeze-frame data from BCM and gateway modules. Document occurrence conditions.
Verify battery voltage and health. If low or flaky, charge or replace battery before further tests and clear codes, then re-check.
Visually inspect BCM and connectors for moisture, corrosion, damage. Dry/clean connectors and reseal if needed.
With ignition on, measure direct power and ground at BCM connector pins. Confirm within specification and good continuity to chassis ground.
Check CAN/LIN bus wiring for continuity, shorts to ground/power, and proper termination. Repair any wiring faults and retest communications.
Attempt to communicate with BCM using manufacturer-level scan tool. If communication is intermittent or fails, trace wiring and bus integrity.
If wiring and power/ground are good and communications healthy, check for available software updates or known technical service bulletins (TSBs). Reflash/reprogram BCM per manufacturer procedure if required.
If reflashing fails or the module continues to report internal faults after correct power, grounds, and communications are confirmed, consider replacement of the BCM with correct part number and programming. Program/configure the new unit per manufacturer procedures.
After any repair or reflash, clear codes, perform function tests for body systems, and road test. Re-scan for reoccurrence and monitor long-term.

Likely causes

Failed internal component or degraded solder joint in BCM
Corrupted firmware following battery drain or interrupted programming
Loose or corroded power/ground connector at the BCM
CAN bus short/open or high bus error rate causing internal watchdogs to trigger
Incorrectly programmed or incompatible replacement BCM

Fault status

⚠️ Status

BCM internal fault recorded. May be stored as a permanent or active fault depending on module implementation. Affects body electrical functions and may require module reprogramming or replacement.

🔴 Repair difficulty: Hard

⏱️ Diagnostic time: 1.0-3.0 hours

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B2399 — Body Control Module (BCM) — Internal Fault