B3411

Code

Generic B — Body

Body Control Module — Subsystem Fault

Brand: Generic

Type: B — Body

Views: UK: 14 EN: 22 RU: 20

AI status

Completed

ready

Completed 100%

Page language: EN

Causes

Faulty BCM hardware (internal component failure)
Corroded/damaged BCM connector or wiring harness
Low or intermittent battery voltage / poor power supply
Poor ground connection to BCM
Loss of network communication (CAN/LIN) or bus errors
Water intrusion or physical damage to BCM

Symptoms

Multiple body electrical functions inoperative or intermittent (locks, lights, wipers, interior features)
Dash warning lights related to body systems
Modules not responding to diagnostic tool or slow to respond
Keyless entry/remote start or alarm problems
Erratic behavior of convenience systems ( dome light, power windows, mirrors )

What to check

Read stored, pending, and freeze-frame data with a capable scan tool; record all related DTCs and timestamps
Confirm current battery voltage (resting and while cranking) and charging system output
Inspect BCM connector and wiring for corrosion, bent pins, water entry, or damage
Check BCM fuses and related relays for continuity and proper operation
Verify good ground(s) for BCM; measure voltage drop between battery negative and BCM ground while operating affected circuits
Scan vehicle network (CAN/LIN) for other module faults or loss of communication codes

Signal parameters

Battery voltage at BCM: ~12.4–12.7 V at rest; ~13.5–14.8 V with engine running (nominal)
Wake/sleep control lines: toggled by ignition/BCM requests; should switch state when key on/off
CAN bus (recessive): CAN_H ≈ 2.5 V, CAN_L ≈ 2.5 V; dominant state ~CAN_H ≈ 3.5 V and CAN_L ≈ 1.5 V (verify with scope)
LIN bus: single-wire serial; idle near battery voltage, pulses to ground during communication (verify per vehicle spec)
Diagnostic response: BCM should respond to a service tool request within a few hundred milliseconds when network healthy
Ground voltage drop: less than 0.1 V between BCM ground and battery negative during normal operation

Diagnostic algorithm

Connect a full-function scan tool. Read all DTCs including U-codes and B-codes. Save freeze frame and live data.
Note whether B3411 is stored, pending, or active. Clear codes and reproduce condition to confirm repeatability.
Check battery state and charging system. Repair low-voltage or charging faults before further diagnosis.
Visually inspect BCM and connector for moisture, corrosion, damaged pins, or loose mating. Repair or reseal as needed.
Verify BCM power and ground circuits: check fuses, relays, and perform voltage-drop tests on power and ground while operating affected loads.
Inspect wiring harness for chafing, shorts to chassis, or recent repairs that could cause intermittent faults.
Scan the vehicle network for lost-communication codes (U0100, U0140, etc.). Use an oscilloscope or CAN/LIN monitor to check signal integrity on data lines.
If wiring, power, and communications are good, check for available BCM software updates and reflash per OEM procedures.
If reflash and repairs do not clear faults, consider bench testing or replacement of the BCM. Follow vehicle immobilizer/programming/security procedures when replacing.
After repair or replacement, perform function tests, clear codes, and verify the condition does not return; complete any required relearns or module programming.

Likely causes

Intermittent power/ground to the BCM (poor battery connection, blown fuse, loose ground)
Corroded or damaged BCM connector or nearby harness
Communication error on CAN or LIN bus (other module failing or shorting the bus)
BCM firmware fault requiring reflash or replacement

Fault status

⚠️ Status

BCM subsystem fault detected. Code may be stored, pending or active depending on event occurrence. Check power/ground, communications, and subsystem components.

🟡 Repair difficulty: Medium

⏱️ Diagnostic time: 0.5-3.5 hours