B0230

Code

Generic B — Body

Body CAN Bus Communication Fault

Brand: Generic

Type: B — Body

Views: UK: 19 EN: 18 RU: 24

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Page language: EN

Multiple body systems malfunctioning or behaving intermittently (doors, lighting, climate, keyless entry)
Illuminated communication-related warning lights on dash
Inability for scan tool to communicate with one or more control modules on body CAN
Stored or pending U-codes for lost communication (e.g., U0100, U0073)
Features operate unpredictably or only when wiring is moved (intermittent)

Retrieve all current and history DTCs from all modules (scan tool capable of body CAN and gateway networks)
Note which modules report loss of communications and whether the fault is persistent or intermittent
Visually inspect CAN wiring harness and connectors for damage, corrosion, or contaminants
Check battery voltage and charge state; inspect battery positive, negative and main ground connections
With ignition on, use a scan tool to monitor CAN message traffic and check for missing IDs or a single module spamming the bus
Measure CAN termination resistance across CAN_H to CAN_L with ignition off (expected ~60 ohms for many systems)

Record all DTCs and freeze frame data from every module; save or print scan tool logs
Identify which physical CAN network (body CAN, gateway, or central CAN) is affected and list modules that lose communication
Check battery state of charge and main power/ground connections; repair/clean and retest if low/poor
Visually inspect wiring and connectors along known routing for body CAN harness; repair any obvious damage or corrosion
With ignition on, monitor CAN traffic with an oscilloscope or capable scan tool; verify presence of expected message IDs and normal waveform shapes
Measure termination resistance between CAN_H and CAN_L with ignition off; verify proper termination (~60 Ω typical)
If a specific module is suspected, disconnect that module (following OEM precautions) and re-check the bus for normal traffic to isolate the faulty node
If intermittent, perform wiggle and flex tests on wiring and connectors while monitoring bus errors to locate intermittent shorts or opens
Inspect and test power/ignition feeds and grounds for each module on the body CAN; repair high resistance connections
If wiring and power are good, consult software/ECU update bulletins and reflash or update module software per manufacturer procedures
After repairs, clear DTCs, monitor live CAN communications, and road test to ensure fault does not return

Open or short in CAN_H or CAN_L wiring near body control module (BCM)
Failing BCM or another module flooding the bus with errors
Single connector with moisture corrosion at a module on the body CAN trunk
Missing/failed 60 ohm termination (or dual 120 ohm) at one or both ends of the bus
Low system voltage from a weak battery or poor ground connections causing intermittent comms