B10A6

Code

Generic B — Body

Body Control Module (BCM) Internal Fault

Brand: Generic

Type: B — Body

Views: UK: 12 EN: 17 RU: 15

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Page language: EN

Causes

BCM internal hardware failure (microcontroller, memory, power management)
Corrupted or failed BCM software/firmware
Low or unstable supply voltage (battery/charging system issues, voltage spikes)
Poor power/ground connections or blown fuse/relay to BCM
Water intrusion, corrosion or physical damage to BCM or connector
CAN/LIN bus faults or shorted communications wiring causing internal errors

Symptoms

Multiple body electrical faults (locks, lights, wipers, HVAC, instrument cluster)
Intermittent or permanent loss of BCM-controlled functions
Warning lamp(s) illuminated (generic or module-specific)
Modules not responding to diagnostic requests or slow/no communication on CAN/LIN
Keyless entry/remote/fob, alarm or immobilizer malfunctions
Parasitic battery drain or inability to enter sleep mode

What to check

Read and record stored DTCs, freeze frame and module software/calibration IDs with a capable scan tool
Verify battery state of charge and charging system voltages (engine off and running)
Inspect BCM and connector for moisture, corrosion, loose pins or physical damage
Check fuses and relays feeding BCM (replace if suspect) and measure supply voltage at BCM power pins
Verify good ground(s) — measure continuity to chassis and battery negative
Check CAN/LIN bus wiring for shorts/opens and measure bus voltages; verify other modules respond

Signal parameters

BCM main supply (ignition ON): approx. 11–14.5 V (vehicle-dependent)
BCM standby supply (key off): near battery voltage if boxed wake circuits present; verify expected sleep voltages per vehicle documentation
Ground resistance from BCM chassis ground to battery negative: typically
CAN bus idle voltages: each CAN line ~2.5 V (differential ~0 V); dominant state changes should show expected differential swing — verify with scope
Module diagnostic response: BCM should respond to diagnostic request within normal tool timeouts (varies by manufacturer)

Diagnostic algorithm

Connect a professional scan tool and record all current and historic DTCs, freeze frame data, and BCM software/calibration ID.
Verify battery voltage and charging system health. Charge or replace battery if low; retest to eliminate low-voltage causes.
Inspect BCM area and connector for moisture, corrosion, bent pins or physical damage. Repair or clean as needed.
Check fuses/relays and measure power at the BCM power pins (both constant and switched supplies). Repair wiring or replace fuse/relay if faulted.
Verify ground connections for low resistance and good contact; repair grounds if high resistance found.
Check CAN/LIN communication: scan other modules, measure idle voltages and watch for errors. Repair wiring or isolating nodes if bus faults are present.
With a scope or data logger monitor relevant BCM inputs/outputs while operating affected functions; look for intermittent faults or noise.
Attempt to clear the code and recreate fault conditions. Note whether code returns and under what conditions (hot/cold, vibration, accessory use).
If wiring/power/ground and communications are good, consult OEM technical service bulletins for known BCM software issues and perform recommended reflash/update.
If reflash does not clear the fault and internal hardware failure is suspected, follow OEM procedure for BCM replacement and required programming/pairing. Preserve/restore coding and immobilizer data per manufacturer instructions.
After repair or replacement, verify all body functions and recheck for recurrence of B10A6 and related codes.

Likely causes

Low/unstable battery voltage or poor ground to BCM
Corrosion/water damage at BCM connector or module
Software/firmware corruption requiring reflash
Failed BCM hardware (internal electronics)
Intermittent CAN bus fault causing module internal fault

Fault status

⚠️ Status

BCM internal fault detected. Module reports an internal error that may affect multiple body systems and communications. Further diagnosis required to confirm hardware, software, or wiring cause.

🔴 Repair difficulty: Hard

⏱️ Diagnostic time: 1.0-3.0 hours