Code
B3472
HUMMER
B — Body
Body Control Module internal memory fault
AI status
Completed
Completed
100%
Causes
- Corrupted BCM internal memory (EEPROM/flash)
- Interrupted programming or software update
- Low or unstable battery voltage during write operations
- Failed BCM hardware (memory chip or controller)
- Water ingress, corrosion or physical damage to BCM or connector
- CAN/vehicle network disturbances causing memory write errors
Symptoms
- Illuminated malfunction indicator lamp or service message
- Intermittent or persistent loss of body functions (locks, lights, windows, etc.)
- BCM not responding to diagnostic scan tool or limited functionality
- Multiple unrelated body/network DTCs present
- Incorrect vehicle configuration (options not recognized)
- Vehicle may not go to sleep/wake correctly or show parasitic battery drain
What to check
- Retrieve all stored codes and freeze frame with an OEM-capable scan tool; note occurrence pattern
- Check battery voltage and state of charge; ensure stable 12.0–14.5 V during testing
- Visually inspect BCM and connector for water damage, corrosion, bent pins or loose connections
- Verify power and ground at BCM (measure voltage at power pin(s) and continuity to chassis ground)
- Confirm BCM responds to diagnostic communication and can provide module ID and software/calibration info
- Check CAN/vehicle network integrity (CAN High/Low voltages, continuity, bus termination) and for related U-codes (e.g., U0100)
Signal parameters
- Battery voltage at BCM supply terminal (expected ~12.0–14.5 V with engine off/run)
- Ground resistance between BCM ground and chassis (should be low;
- CAN High/Low idle voltages (~2.5 V midpoint; differential ~2.5 V) and presence of traffic
- Module identification and software/part number available via scan tool
- EEPROM/flash checksum or CRC status flags shown by OEM diagnostic tool (if available)
- Wake/sleep state transitions and module supply current (parasitic draw if module not sleeping)
Diagnostic algorithm
- Read and record B3472 and all other stored DTCs and freeze frame data with an OEM-capable scan tool.
- Attempt to clear codes and perform ignition cycles; confirm whether B3472 returns and note conditions when it appears.
- Verify battery charge and cranking voltage; ensure stable power during diagnosis and potential reflash procedures.
- Visually inspect BCM housing and connector for damage, corrosion, moisture, or loose pins; repair any issues and retest.
- Measure supply voltage and grounds at the BCM connector; repair any poor power/ground connections and retest.
- Check vehicle network health: verify CAN communications to and from BCM, check for bus errors, and confirm other modules see the BCM.
- If available, use OEM diagnostic procedures to read module internal memory status, configuration, and EEPROM checksum/CRC.
- Review service history for recent software updates or interrupted programming. If a reflash was interrupted, attempt a controlled reprogram/recover using the OEM scan tool following factory instructions; ensure stable battery or use a battery charger.
- If reprogramming fails or internal diagnostics indicate memory hardware failure, consider replacing the BCM. Obtain correct replacement part and perform required module programming/configuration and vehicle re-teach procedures with OEM tools.
- After repair or replacement, verify all body functions, clear codes, and perform road/operation checks to confirm the fault does not recur.
Likely causes
- Incomplete or failed software reflash/update of BCM
- Battery discharged or removed while BCM was writing calibration data
- Faulty BCM power supply or intermittent ground
- Damaged BCM connectors or corroded pins causing transient faults
- Internal EEPROM/flash wear-out or controller failure
- Aftermarket equipment installation that altered BCM configuration or bus signals
Fault status
Status
BCM internal memory fault — internal EEPROM/flash checksum or memory failure detected; module configuration or stored data may be corrupted.
Repair difficulty: Hard
Diagnostic time: 2-4 hours
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