Code
B2641
HUMMER
B — Body
Keyless Entry Antenna Circuit Fault
Views:
UK: 13
EN: 15
RU: 11
AI status
Completed
Completed
100%
Causes
- Damaged or disconnected antenna/coaxial harness
- Corroded or loose connector at antenna or module
- Short to voltage or ground in antenna circuit
- Faulty keyless entry antenna (module/loop)
- Faulty body control module (BCM) or antenna interface
- Intermittent wiring or pin damage (water intrusion)
Symptoms
- Keyless entry (lock/unlock) or passive unlock not working reliably
- Reduced range for remote/keyless entry
- No response from key fob while close to vehicle
- Related convenience features fail or are intermittent
- DTC stored and possibly warning lamp or message
What to check
- Scan tool: read freeze frame, DTC status, and related B/C and U codes
- Verify vehicle battery voltage and system power supply
- Visual inspection of antenna location, connectors, and wiring for damage or corrosion
- Check for water intrusion in antenna area (door, pillar, trunk, roof)
- Measure continuity and resistance of antenna leads to module
- Backprobe connector and measure signal/voltage with keyless events
Signal parameters
- Antenna supply voltage: typically 9–12 V (verify vehicle spec)
- Ground continuity: near 0 Ω to chassis ground
- Antenna feed impedance: low-ohm continuity; open or very high indicates break
- RF coupling: presence of RF pulses when a key is used (requires oscilloscope/RF tool)
- CAN/BUS messages: body module reporting antenna status; check for communication faults
Diagnostic algorithm
- Retrieve freeze frame data and all stored DTCs with a factory-capable scan tool. Note if DTC is current, intermittent, or historic.
- Verify battery voltage is within normal range. Low system voltage can create false faults.
- Perform a visual inspection of the antenna(s), mounting area, and harness for damage, pins pushed out, or corrosion. Repair or secure connectors if needed.
- With connector disconnected, inspect pins for corrosion and continuity; clean and apply dielectric grease if minor corrosion present. Re-test.
- Measure resistance/continuity between antenna connector and the body control module pin. Look for opens or high resistance. Repair wiring as required.
- Backprobe antenna power and ground while cycling keyless entry to confirm correct supply and ground switching. Compare to vehicle-specific reference values.
- If wiring checks good, swap or bench-test the antenna module (if serviceable) or install a known-good antenna to verify fault clears.
- Check for related modules reporting errors on the data bus. Repair any communication faults before replacing hardware.
- If hardware replacement is performed, clear DTCs and verify normal operation and no return of the code after road test and multiple keyless operations.
- If tests point to BCM fault after verifying antenna and wiring, consult manufacturer diagnostics for BCM bench tests or reprogramming before replacement.
Likely causes
- Open or high-resistance connection at antenna connector
- Water intrusion/corrosion at antenna connector
- Broken or chafed antenna coax/conductor
- Faulty keyless entry antenna unit
Fault status
Status
Keyless entry antenna circuit fault — open/short/high resistance or communication error detected.
Repair difficulty: Medium
Diagnostic time: 0.5-2.0 hours
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