B0290

Code

Generic B — Body

Body Control Module Communication Fault

Brand: Generic

Type: B — Body

Views: UK: 12 EN: 22 RU: 10

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One or more body functions inoperative or intermittent (locks, windows, lighting, wipers)
Inability to communicate with BCM using a scan tool
Other modules report lost communication or multiple network errors
Warning lights or message center alerts related to body systems
Battery drain, fuse blows, or erratic behaviour of accessories

Connect a scan tool, read all module addresses and stored/current codes; note communication status
Record battery voltage with key off and during cranking (12.2–12.8 V at rest typical)
Visually inspect BCM connector(s) for corrosion, bent pins, water, or damage
Check BCM power and ground circuits for proper voltage and good continuity
Verify fuses and relays related to BCM power/ignition circuits
Inspect CAN/LIN wiring harness for chafing, pinches, or repairs; perform wiggle tests

CAN bus recessive level: both CAN-H and CAN-L ≈ 2.5 V
CAN dominant differential: CAN-H ≈ 3.5 V, CAN-L ≈ 1.5 V (differential ≈ 2.0 V)
Termination resistance (CAN-H to CAN-L): ≈ 60 ohms (two 120 Ω terminators in parallel)
LIN bus idle: pulled up to battery voltage via resistor (signal low when driven)
Battery voltage: should be stable and >12 V with key off; >11 V during cranking

Use scan tool: confirm B0290 details, check for related DTCs and live data where available.
Verify vehicle battery voltage and charging system; charge or replace battery if low.
Inspect BCM connector(s) and harness for corrosion, water intrusion, damage or loose pins; repair as needed.
Check BCM power/ignition fuses and relay operation; measure voltage at BCM power pins with connector connected.
Test ground integrity: measure voltage drop between BCM ground and chassis during a load/wiggle test.
Probe CAN bus at BCM: measure CAN-H and CAN-L voltages at idle and during activity; compare to expected signal_params.
Check bus termination resistance and continuity to other module connectors; isolate segments if bus short suspected.
Disconnect non‑OEM accessories or modules that share the bus; see if communication is restored.
If wiring and bus checks OK, attempt to reflash or verify BCM software/calibration per manufacturer procedures.
If programming fails or faults persist with correct wiring/power/termination, consider replacing BCM. After replacement, program and relearn per OEM instructions and confirm all related modules communicate.
Clear codes and verify all affected systems operate normally before returning vehicle to service.