B1523

Code

Other B — Body

Keyless Entry Circuit Failure

Brand: Other

Type: B — Body

Views: UK: 28 EN: 105 RU: 36

AI status

Completed

ready

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Page language: EN

Causes

Blown fuse for keyless entry or body electronics
Dead/low key fob battery
Damaged or disconnected wiring or connector in keyless entry circuit
Poor ground at body/control module
Faulty keyless entry (body) control module or receiver
Damaged or disconnected antenna or antenna amplifier

Symptoms

Remote/keyless lock or unlock does not operate
Intermittent or unreliable remote response
Keyless entry LED (if equipped) does not flash on command
Doors unlock/lock only with manual key
Vehicle will not remote-start or shows keyless entry error message
Security/anti-theft lamp may be illuminated or indicate a fault

What to check

Scan vehicle with an appropriate diagnostic tool and read freeze frame and module data; record all related codes
Check battery state-of-charge and ensure vehicle battery voltage is >= 12.4 V during tests
Inspect fuses and fusible links for the keyless/body modules; replace if blown
Check key fob battery and verify fob operation with a spare fob if available
Visually inspect wiring, connectors, and antenna lead for damage, corrosion, pins pushed out or water intrusion
Verify module grounds and measure continuity between module ground and chassis

Signal parameters

Module supply voltage: nominal battery voltage (12–14.5 V) at keyless entry module pins
Ground continuity:
RF receive: remote transmit frequency typically 315 MHz or 433 MHz (vehicle specific) — receive level should be consistent when fob is presented close to antenna
CAN/LIN messages: keyless module should show regular network heartbeats and lock/unlock command frames in scanner data
Digital output: lock/unlock driver output logic (0/5 V or module-specific switched battery output) when remote command received
Antenna continuity/resistance: measure per vehicle wiring diagram — open or very high resistance indicates fault

Diagnostic algorithm

Verify and record the exact code(s) and freeze-frame with a scan tool. Note any related U- or B-codes. Clear the code and attempt to reproduce.
Confirm vehicle and key fob batteries have adequate charge. Replace key fob battery and test operation with a known-good spare fob if available.
Inspect and test fuses related to body/keyless systems; replace any blown fuses and re-scan.
With ignition off, visually inspect connectors, antenna lead(s), and wiring harness routing to receiver/module for damage, chafing, or corrosion. Repair or reconnect as required.
Verify ground(s) and power feed to the keyless entry module. Measure module supply voltage and ground continuity while operating the remote to check for voltage drops.
Use a diagnostic tool to monitor module inputs/outputs and network communication while commanding remote lock/unlock. Confirm whether commands reach the module and whether module sends lock/unlock outputs.
Test antenna/receiver: if accessible, check antenna continuity and connection to module. If RF signal measurements are available, confirm the receiver is detecting fob transmissions at close range.
If module receives commands but actuators do not respond, isolate downstream actuators (door lock actuators, door switches) and test their circuits for continuity and operation.
If wiring and peripherals test good but module shows internal fault or does not respond to commands, consider reflashing software if available, then retest. If reflashing not available or unsuccessful, replace the keyless entry module per manufacturer procedure.
After repairs, clear codes, function-test keyless operations multiple times and road/test as required to confirm repair. Document findings and retained codes.