B2710

Code

Generic B — Body

Body Control Module communication fault

Brand: Generic

Type: B — Body

Views: UK: 22 EN: 27 RU: 25

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Page language: EN

No response from BCM to scan tool or intermittent 'no communication' messages
Multiple body functions inoperative (locks, lights, windows, wipers) or behaving erratically
Multiple unrelated modules showing communication lost codes
Warning lamps or messages on dash about communication or module faults
Possible battery drain if BCM stuck awake

Read and record all network and BCM-related codes with an OEM-level scan tool
Verify battery voltage (12.4–12.8 V engine off) and measure voltage during cranking
Check relevant fuses and relays for BCM power and accessory feeds
Inspect BCM connector for corrosion, bent pins, moisture, or aftermarket splices
Perform wiggle test on harnesses while monitoring communication messages or CAN activity
Check for other stored U-codes indicating another module lost that could affect bus health

Battery and BCM supply voltages (IGN, BATT) and ground continuity
CAN bus voltage levels: CAN_H ~2.5 V idle (dominant ~3.5 V), CAN_L ~2.5 V idle (dominant ~1.5 V)
Differential voltage on CAN (dominant ~2.0 V), bus idle differential ~0 V
Bus termination resistance (~60 Ω across CAN_H and CAN_L at key points)
Bus error counters, TX/RX frame counts, and 'bus off' status via scan tool
Typical bus baud rates (250 kbps, 500 kbps, or manufacturer-specific) and message IDs for BCM

Connect OEM-capable scan tool and read all DTCs and live network status; note any U-codes and freeze frame data.
Record whether BCM responds to diagnostic requests. Attempt to communicate to other modules to determine if problem is BCM-specific or bus-wide.
Verify vehicle battery state-of-charge and wiring to BCM fuses/relays; restore proper battery voltage if low and retest.
Visually inspect BCM connector and harness for damage, corrosion, water intrusion, or aftermarket splices. Repair or clean as needed.
Check power and ground circuits at the BCM with a multimeter (voltage under load, resistance to chassis ground).
Measure CAN_H and CAN_L voltages at the BCM with key ON and engine OFF. Confirm idle and dominant voltage behavior and check termination resistance.
If a short/low resistance is suspected, disconnect BCM connector (with ignition OFF) and measure bus resistance and voltages to isolate whether BCM is loading the bus.
If fault persists and wiring checks good, use oscilloscope to inspect CAN waveform quality (ringing, missing edges, noise).
Remove or disable suspected aftermarket accessories and retest communications.
If BCM hardware or software is suspected after wiring isolation, consult manufacturer guidance for BCM reprogramming or replacement and follow correct replacement and coding procedures.
After repairs, clear codes and verify normal communication over time and through key cycles; monitor for reoccurrence.