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Home / DTC / B2641 — Keyless Entry Antenna Circuit Fault

B2641 — Keyless Entry Antenna Circuit Fault

Detailed page for trouble code B2641.

34,364codes
59brands
11,873generic
22,491specific
All codes P-codes (Powertrain) B-codes (Body) C-codes (Chassis) U-codes (Network/User) Tesla Alerts
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Code

B2641

HUMMER B — Body

Keyless Entry Antenna Circuit Fault

Brand: HUMMER
Type: B — Body
AI status
Completed
ready
Completed 100%
Page language: EN

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

  1. Retrieve freeze frame data and all stored DTCs with a factory-capable scan tool. Note if DTC is current, intermittent, or historic.
  2. Verify battery voltage is within normal range. Low system voltage can create false faults.
  3. 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.
  4. With connector disconnected, inspect pins for corrosion and continuity; clean and apply dielectric grease if minor corrosion present. Re-test.
  5. Measure resistance/continuity between antenna connector and the body control module pin. Look for opens or high resistance. Repair wiring as required.
  6. Backprobe antenna power and ground while cycling keyless entry to confirm correct supply and ground switching. Compare to vehicle-specific reference values.
  7. If wiring checks good, swap or bench-test the antenna module (if serviceable) or install a known-good antenna to verify fault clears.
  8. Check for related modules reporting errors on the data bus. Repair any communication faults before replacing hardware.
  9. If hardware replacement is performed, clear DTCs and verify normal operation and no return of the code after road test and multiple keyless operations.
  10. 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

Similar codes

B2640 B2642 B2650 B2651 U0140 U0121
Repair manuals

Manual library for HUMMER

138

Browse 138 HUMMER manuals: repair procedures, diagnostics, wiring diagrams, component locations, service data and Labor Times by year, model and trim.

HUMMER

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Code

B2641

LAND ROVER B — Body

Body Control Module (BCM) internal fault

Brand: LAND ROVER
Type: B — Body
AI status
Completed
ready
Completed 100%
Page language: EN

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

  1. Retrieve freeze frame data and all stored DTCs with a factory-capable scan tool. Note if DTC is current, intermittent, or historic.
  2. Verify battery voltage is within normal range. Low system voltage can create false faults.
  3. 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.
  4. With connector disconnected, inspect pins for corrosion and continuity; clean and apply dielectric grease if minor corrosion present. Re-test.
  5. Measure resistance/continuity between antenna connector and the body control module pin. Look for opens or high resistance. Repair wiring as required.
  6. Backprobe antenna power and ground while cycling keyless entry to confirm correct supply and ground switching. Compare to vehicle-specific reference values.
  7. If wiring checks good, swap or bench-test the antenna module (if serviceable) or install a known-good antenna to verify fault clears.
  8. Check for related modules reporting errors on the data bus. Repair any communication faults before replacing hardware.
  9. If hardware replacement is performed, clear DTCs and verify normal operation and no return of the code after road test and multiple keyless operations.
  10. 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

Similar codes

B2640 B2642 B2650 B2651 U0140 U0121
320

Browse 320 LAND ROVER manuals: repair procedures, diagnostics, wiring diagrams, component locations, service data and Labor Times by year, model and trim.

LAND ROVER

Your experience will help others
+100 karma for a short comment :)
Keep it short and practical. Up to 500 characters.
Send to email

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