B2288

Code

Generic B — Body

Body Control Module CAN Communication Fault

Brand: Generic

Type: B — Body

Views: UK: 8 EN: 12 RU: 5

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Page language: EN

Causes

Open, short, or high resistance in CAN bus wiring (CAN High, CAN Low)
Bad or corroded connector(s) at BCM or other modules on the same bus
Missing or incorrect termination resistor(s) or wrong termination resistance
Loss of BCM supply voltage(s) or ground(s)
Software/configuration mismatch or corrupted BCM programming
Faulty BCM or another control module transmitting bus errors

Symptoms

Multiple body systems non-functional or intermittent (doors, lighting, wipers, HVAC controls)
Warning or communication messages on dash (CAN bus, Network Communication, Check Vehicle)
Other modules show U-codes (lost communication with BCM)
Random/erratic operation of convenience features or instrument cluster
Possible no crank/no start if BCM provides immobilizer or starter enable messages

What to check

Use a scan tool to read B2288 plus related codes from BCM and other modules; capture freeze-frame and active/occurrence counts
Inspect BCM connectors and harness for corrosion, bent pins, water intrusion, or damage
Check battery voltage and BCM fuse(s); verify good power and ground at BCM
Verify presence of correct CAN termination (120 ohm between CAN_H and CAN_L) with ignition off
Measure idle voltages on CAN_H and CAN_L with a DMM; compare to known-good specs
Use a serial-data capable scan tool or oscilloscope to view CAN frames and check for noise, dominant-stuck, or missing messages

Signal parameters

Recessive idle: CAN_H ≈ 2.5 V, CAN_L ≈ 2.5 V (each to chassis)
Dominant state: CAN_H ≈ 3.5 V, CAN_L ≈ 1.5 V (differential ≈ 2.0 V)
Differential idle ≈ 0 V; dominant differential ≈ 2 V
Bus termination: nominal 120 ohm between CAN_H and CAN_L (measured with power off)
Common CAN bit rates: 125 kbps, 250 kbps, 500 kbps (verify vehicle-specific rate)
Expected steady periodic messages from BCM and other modules — missing or garbled frames indicate fault

Diagnostic algorithm

Record all stored DTCs and freeze-frame data from BCM and other modules; note occurrence history.
Visually inspect BCM connector(s), pins and wiring harness for damage, corrosion, water, or rodent damage.
Verify vehicle battery voltage and check BCM fuses and power/ground circuits for proper continuity and voltage at key pins.
With ignition ON, measure CAN_H and CAN_L voltages at the BCM connector with a DMM; confirm idle voltages ~2.5 V.
With power off, measure resistance between CAN_H and CAN_L at the BCM to confirm termination ≈ 120 ohms (across the bus).
Use a CAN-capable scan tool to monitor live data and see if BCM transmits or receives expected messages; note missing or error frames.
If available, use an oscilloscope to inspect waveform for noise, reflections, dominant-stuck, or abnormal levels; if bus is noisy, isolate segments.
Isolate the circuit by disconnecting non-critical modules one at a time (or segment terminators) to find the node causing errors — start with recent repairs or aftermarket modules.
Repair any damaged wiring, pins, or connectors; clean corrosion and apply dielectric grease where appropriate; replace broken termination resistors.
If wiring and power/grounds are good but communication still fails, check for BCM software updates or reprogramming procedures; reflash or reconfigure BCM per manufacturer procedures.
Replace BCM only after confirming external wiring, power/grounds, and bus integrity are correct; program/configure the new BCM and verify operation.
Clear codes and road-test; verify DTC does not return and affected systems operate normally.