B06A0

Code

Generic B — Body

Body Control Module Internal Fault

Brand: Generic

Type: B — Body

Views: UK: 4 EN: 8 RU: 8

AI status

Completed

ready

Completed 100%

Page language: EN

Causes

Internal BCM hardware failure (failed electronic component, solder joint, or PCB fault)
Corrupted or failed firmware/flash memory
Interruption during previous software update or coding
Loss or abnormal power supply (low battery, voltage spikes, unstable charging)
Poor or missing ground connections
Water intrusion, corrosion, or physical damage to module or connector

Symptoms

Multiple body functions inoperative or intermittent (locks, windows, lighting, wipers, etc.)
Warning lights or body system messages on instrument cluster
Loss of communication with BCM reported by scan tool or other modules
Erratic behavior of lighting, door locks, or convenience features
Possible parasitic battery drain or fuse blowing
Inability to program or communicate reliably with the module

What to check

Connect a quality scan tool and read all stored and pending codes from BCM and other modules; note freeze-frame data and time stamps
Check for additional communication (U- codes) or related B-codes in other modules
Measure battery voltage with ignition off and while cranking; verify charging system voltage with engine running
Visually inspect BCM connector and harness for corrosion, bent pins, water intrusion, damaged wires, or evidence of previous repairs
Verify clean, low-resistance ground(s) and battery positive feed to BCM
Confirm ignition/wake inputs and CAN/LIN bus presence using a multimeter or scope

Signal parameters

Battery/supply voltage at BCM: nominal 11.5–14.5 V (check during key ON and engine running)
Ignition feed/wake signal: switch/IGN feed present when expected (verify with DMM)
CAN bus idle voltages: CAN_H ≈ 2.5 V, CAN_L ≈ 2.5 V (dominant approx. CAN_H ~3.5 V / CAN_L ~1.5 V)
CAN differential when active: approx. 2.0 V differential during frames (oscilloscope ideal)
Ground circuit resistance: low-ohm continuity (near 0 Ω to chassis ground)
Module wake/sleep activity: expected wake pulses on LIN/CAN when key or door events occur

Diagnostic algorithm

Record customer complaint and any recent events (battery change, repairs, flooding, reflash attempts).
Use scan tool: read and document all codes from BCM and other modules; check for stored U-codes or multiple module errors.
Verify battery state-of-charge and charging system; charge battery or connect known-good power supply if low.
Visually inspect BCM and connector for water, corrosion, damaged pins, or loose locking tangs; repair harness as required.
With connector attached, measure BCM primary power and ground circuits with a DMM; verify correct voltages and low ground resistance.
Check CAN/LIN bus physical layer: measure idle voltages, check for shorts to battery/chassis, and verify proper termination. Use oscilloscope if available to view bus signals and noise.
Clear the code and perform functional tests to see if fault returns; attempt to reproduce the condition under normal operating conditions.
If communications are intermittent, try another scan tool and verify software access. Attempt to reflash or update BCM software with OEM tool if newer calibration exists and power is stable.
If fault persists after power/ground and bus checks and reflash attempts, consider bench testing the BCM or substituting a verified-good unit (follow OEM immobilizer/security and coding procedures).
If replacement is required, install new or reconditioned BCM, perform required programming/coding and relearn procedures, then recheck all related systems and clear codes.
After repair, road-test and re-scan to confirm the fault does not return and that all affected body functions operate normally.

Likely causes

Low or unstable battery/charging system voltage at time of fault
Poor ground at BCM or chafed/loose connector
Corroded/wet connector or evidence of moisture inside BCM
Interrupted reflash or incorrect software level
Internal component failure inside BCM (age, thermal stress)

Fault status

⚠️ Status

Stored — BCM internal fault detected. Indicates an internal hardware or firmware error, or related power/communication issue. Further electrical and communication diagnostics required.

🔴 Repair difficulty: Hard

⏱️ Diagnostic time: 1.5-4.0 hours