B0601

Code

Generic B — Body

Body Control Module — Network Communication Fault

Brand: Generic

Type: B — Body

Views: UK: 17 EN: 26 RU: 25

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Page language: EN

One or more body systems inoperative (lighting, locks, windows, wipers, climate controls)
Intermittent or no communication with BCM via scan tool
Multiple modules reporting communication-related codes
Warning lights or instrument cluster messages about system faults
Remote keyless entry, immobilizer, or starting problems
Modules entering 'bus-off' state or repeating network fault codes

Read all stored/active U/B/P codes and note freeze-frame and occurrence counts
Confirm battery voltage is stable and above ~12.2 V during cranking and testing
Verify (and wiggle) BCM power and ground circuits at the module for secure connections
Visually inspect BCM connector and wiring for corrosion, bent pins, or water intrusion
Check for other modules reporting network faults (U0073, U0100, U0140 etc.)
Measure CAN bus idle voltages at BCM connector and at other nodes

Typical CAN recessive voltage: CAN_H ≈ 2.5 V, CAN_L ≈ 2.5 V (each) when idle
CAN dominant state: CAN_H ≈ 3.5 V and CAN_L ≈ 1.5 V (approx. 2.0 V differential)
Expected differential voltage when dominant ≈ 2.0 V
Termination resistance (two 120 Ω terminators in parallel) ≈ 60 Ω between CAN_H and CAN_L with ignition off
Common bus data rates vary by vehicle: typically 250 kb/s or 500 kb/s — verify vehicle-specific bus speed
LIN/other single-wire networks will show different expected voltages; consult vehicle schematics

Record all codes, freeze frame, and current network status with a capable scan tool; do not clear codes yet.
Verify battery voltage and charge level; recharge or stabilize battery if low and retest.
Inspect BCM power and ground fuses/relays; test for proper permanent and switched power at BCM connector.
Visually inspect BCM connector and wiring for damage, corrosion, water intrusion, or pushed-out pins.
Check for other communication codes (U-codes) that may indicate a different module is failing first.
With ignition on, measure CAN_H and CAN_L at the BCM harness and at a known-good node; compare to expected signal parameters.
Measure resistance between CAN_H and CAN_L with ignition off; confirm ≈60 Ω (vehicle specific).
Use an oscilloscope or high-quality CAN-capable scan tool to view waveform for noise, stuck-dominant, or missing activity; note any abnormal frames or bus flooding.
If a noisy or shorted line is suspected, isolate sections of the network by disconnecting connectors or modules one at a time to find the fault source.
If a single other module causes failure when connected, diagnose that module per its codes and wiring.
If wiring and other modules check good, verify BCM software/calibration level and reflash/update per OEM procedure before replacement.
Replace BCM only after confirming wiring, power/ground, and bus integrity; program/configure new module as required, clear codes, and retest all affected systems.

Poor BCM ground or low battery/unstable supply to BCM
Damaged connector pins or corrosion at BCM harness
Broken or shorted CAN_H/CAN_L wiring or connector
Bus termination resistor open or missing (abnormal resistance between CAN_H and CAN_L)
Another module causing bus to go bus-off or flooding the bus with invalid frames
Failed BCM hardware or corrupted software requiring reflash or replacement