Code
B2702
HUMMER
B — Body
Manufacturer-specific body control module fault — consult service manual
Views:
UK: 11
EN: 17
RU: 12
AI status
Completed
Completed
100%
Causes
- BCM internal software or hardware fault
- Loss of power or ground to BCM
- Corroded/damaged BCM connector or wiring
- Intermittent or failed CAN/LIN communication
- Aftermarket electrical accessories or improper repair/modification
Symptoms
- BCM-related functions inoperative or intermittent (lighting, door locks, wipers, etc.)
- Multiple body system warnings or message center alerts
- Loss or erratic vehicle convenience features
- Communication errors on scan tool (no data or invalid data from BCM)
- Possible battery drain or unexpected behavior after ignition off
What to check
- Read all stored codes and freeze frame/pending codes from all modules
- Verify battery voltage (11–14.5 V) and state of charge, check for low system voltage events
- Inspect BCM connectors for corrosion, bent pins, water intrusion, or damage
- Check BCM power and ground circuit fuses and relays
- Scan other modules for network communication errors (U-codes)
- Visually inspect wiring harness routing near doors, kick panels, and under dash for chaffing or moisture
Signal parameters
- Battery supply to BCM: nominal 12–14.5 V with ignition on (check for cranking voltage drop)
- Ground continuity: low ohms between BCM ground and chassis (
- CAN bus activity: valid CAN frames present on CAN high/low when key on (refer to service manual for module IDs and message frequency)
- LIN or serial data lines (if equipped): presence of expected waveform/idle levels per service manual
- Module present/response: BCM should respond to diagnostic requests; absence indicates communication fault
Diagnostic algorithm
- Connect a capable scan tool and record all DTCs and freeze frame data from BCM and other modules
- Confirm code is current (not historical). Note associated symptoms and when they occur (startup, driving, after wash, etc.)
- Verify battery condition and charging system; recharge/replace battery if voltage is marginal and re-check
- Inspect BCM connector and harness for corrosion, moisture, damage; repair any wiring issues and secure connectors
- Check fuses/relays feeding the BCM and verify power/ground circuits with a meter; repair/replace as required
- Check vehicle communication network: verify CAN/LIN voltages and message traffic with a scan tool or oscilloscope; trace and repair any bus faults
- If wiring and power/ground are good, attempt to clear the code and re-evaluate system operation; recreate the symptom to see if code returns
- If code returns and all external checks pass, follow manufacturer procedure for BCM reprogramming/update or calibration (consult service manual for exact flash files and steps)
- If reprogramming does not resolve and BCM hardware tests fail per manual, replace BCM only with correct part and program per procedure
- After repair, perform full functional test and drive cycle to confirm code does not return
Likely causes
- Blown BCM supply fuse or weak battery
- Poor ground at BCM mounting point
- Water intrusion or physical damage to BCM housing
- Short, open or high resistance on BCM power/ground harness
- Corrupted/calibration mismatch after module replacement or failed reprogramming
Fault status
Status
Manufacturer-specific BCM fault recorded. Consult vehicle service manual for module-specific diagnostics, test data and reprogramming/repair procedures.
Repair difficulty: Medium
Diagnostic time: 1.5 - 4.0 hours
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