B28C0

Code

Generic B — Body

B28C0 — Body Control Module Communication Fault

Brand: Generic

Type: B — Body

Views: UK: 6 EN: 9 RU: 11

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Inoperative or intermittent body functions (doors/locks, lights, wipers, interior features)
Multiple communication-related DTCs stored in other modules
Inability to communicate with BCM using a scan tool
Warning lights or message center errors related to electronic systems
Vehicle may fail certain networked features or display degraded operation

Read and record all stored codes and freeze frame data from all modules with a capable scan tool
Verify battery voltage and charging system (idle voltage should be ~12–14.5 V) before testing communications
Visually inspect BCM connector(s) and wiring for damage, corrosion, or moisture
Check BCM power and ground circuits: verify voltages at the BCM power pins and low resistance to battery negative for ground
Measure CAN/LIN bus voltages at the BCM connector with ignition ON (CANH/CANL ~2.5 V idle; dominant CANH ~3.5 V and CANL ~1.5 V typical)
Check termination resistance between CANH and CANL with ignition OFF (~60 ohms for two 120Ω terminators in parallel)

CAN bus recessive idle voltage: CANH ≈ 2.5 V, CANL ≈ 2.5 V (both lines close to mid-supply)
CAN bus dominant voltages: CANH ≈ 3.5 V, CANL ≈ 1.5 V (differential ≈ 2.0 V)
Termination resistance (power OFF) between CANH and CANL ≈ 60 Ω (two 120 Ω terminators in parallel)
Common bus data rates: 125 kbps, 250 kbps, 500 kbps (verify vehicle-specific rate before advanced troubleshooting)
LIN bus idle: pulled up to battery voltage through pull-up resistor; dominant state close to 0.5 V (if vehicle uses LIN for BCM peripherals)

Verify and record all related codes from all modules; note time stamps and freeze frame data.
Confirm battery voltage is adequate (engine OFF and ON); charge or replace battery if low before continuing.
Attempt to communicate with BCM using a manufacturer-capable scan tool. If no communication, try a generic OBD-II tool to verify.
Inspect BCM connectors and pin terminals for corrosion, bent pins, or water intrusion; repair or reseat connectors as needed.
With ignition ON (engine OFF), measure BCM supply voltage and ground integrity at the connector; repair any open/low circuits and fuses/relays.
Probe CANH and CANL voltages at the BCM connector. Compare to expected idle voltages. If abnormal, inspect for shorts to battery/ground or excessive loading.
With power OFF, measure termination resistance between CANH and CANL at two different points to confirm presence of both terminators (~60 Ω).
If intermittent, perform a wiggle test on harness sections while monitoring communication; isolate section causing fault.
Disconnect non-essential modules one at a time (or isolate segments) to determine if another device is causing bus errors or bus-off condition.
If wiring and power/ground are good and the bus is healthy, consider reflashing or reprogramming the BCM per manufacturer procedure. Check for TSBs or software updates.
Replace the BCM only after confirming persistent internal fault and ensuring replacement module is programmed/configured for the vehicle. Clear codes and verify repair.