Code
B1525
ALFA ROMEO
B — Body
Remote unlock circuit short to positive
Views:
UK: 4
EN: 5
RU: 3
AI status
Completed
Completed
100%
Causes
- Shorted unlock output wire to battery positive (B+)
- Stuck or welded relay contact feeding the unlock output
- Faulty door lock actuator with internal short
- Corroded or damaged connector causing high voltage feed into output
- Body Control Module (BCM) internal fault
- Aftermarket alarm/keyless entry wiring error
Symptoms
- Remote/key fob unlock does not work or works intermittently
- Fuse for locks blows repeatedly
- Continuous battery drain when vehicle is off
- Door(s) lock/unlock behave erratically or lock/unlock without command
- Relevant BCM warnings or multiple body system faults stored
What to check
- Read BCM/Body module codes and freeze frame data with a proper scan tool
- Visually inspect wiring harnesses, connectors, and door actuator(s) for damage or corrosion
- Check related fuses and relays for continuity and signs of melting or failure
- Measure voltage at the unlock output terminal with ignition off and while pressing remote
- Disconnect the door actuator/unlock motor and try the unlock command to see if code clears
- Inspect for aftermarket alarm or keyless entry modules and their wiring
Signal parameters
- Normal idle: unlock output = open/high-impedance (no battery feed)
- On unlock command: output expected = switched 12 V pulse (typically 0–1 A depending on actuator)
- Fault condition: persistent ~12 V present at output when command not given (short to B+)
- Resistance of unlock output to battery positive should be high (open); near 0 Ω indicates short
Diagnostic algorithm
- Connect a diagnostic scan tool, confirm B1525 and note any related codes or freeze-frame data.
- Clear codes, attempt remote unlock while monitoring the BCM unlock output voltage/waveform.
- Visually inspect the entire unlock circuit wiring from BCM to door actuators and connectors for abrasion, pinched spots, melted insulation, or corrosion.
- With battery disconnected, perform continuity/resistance check between the unlock output conductor and battery positive. A near-zero reading indicates a short to B+.
- Disconnect the unlock actuator(s) and any intermediate connectors; re-check if the code returns when performing unlock command. If code clears, suspect actuator or wiring in that branch.
- Check unlock relay (if fitted): remove and bench-test for stuck contacts or substitute known-good relay.
- If short persists with actuators disconnected, trace wiring harness and isolate sections using back-probing and a fused jumper to locate the shorted segment.
- Repair damaged wiring or connectors; replace faulty actuator or relay as required.
- If wiring and external components test good, suspect BCM output transistor failure—verify with manufacturer procedures and consider module replacement or reprogramming per service manual.
- After repair, clear codes and perform full function test (multiple lock/unlock cycles, power off soak) to confirm repair and no battery drain.
Likely causes
- Pinched or chafed unlock wire contacting a constant 12V source
- Failed remote unlock relay stuck closed
- Door actuator motor shorted, connecting output directly to battery
- Water intrusion at connector forcing a positive feed
- Incorrectly installed aftermarket remote or alarm harness
Fault status
Status
Remote unlock circuit short to positive detected. Unlock function may be disabled, fuses may blow, or battery drain may occur. Inspect wiring, actuator, relays, and BCM.
Repair difficulty: Medium
Diagnostic time: 0.5-2.5 hours
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Code
B1525
FIAT
B — Body
Remote unlock circuit short to positive
Views:
UK: 3
EN: 6
RU: 3
AI status
Completed
Completed
100%
Causes
- Shorted unlock output wire to battery positive (B+)
- Stuck or welded relay contact feeding the unlock output
- Faulty door lock actuator with internal short
- Corroded or damaged connector causing high voltage feed into output
- Body Control Module (BCM) internal fault
- Aftermarket alarm/keyless entry wiring error
Symptoms
- Remote/key fob unlock does not work or works intermittently
- Fuse for locks blows repeatedly
- Continuous battery drain when vehicle is off
- Door(s) lock/unlock behave erratically or lock/unlock without command
- Relevant BCM warnings or multiple body system faults stored
What to check
- Read BCM/Body module codes and freeze frame data with a proper scan tool
- Visually inspect wiring harnesses, connectors, and door actuator(s) for damage or corrosion
- Check related fuses and relays for continuity and signs of melting or failure
- Measure voltage at the unlock output terminal with ignition off and while pressing remote
- Disconnect the door actuator/unlock motor and try the unlock command to see if code clears
- Inspect for aftermarket alarm or keyless entry modules and their wiring
Signal parameters
- Normal idle: unlock output = open/high-impedance (no battery feed)
- On unlock command: output expected = switched 12 V pulse (typically 0–1 A depending on actuator)
- Fault condition: persistent ~12 V present at output when command not given (short to B+)
- Resistance of unlock output to battery positive should be high (open); near 0 Ω indicates short
Diagnostic algorithm
- Connect a diagnostic scan tool, confirm B1525 and note any related codes or freeze-frame data.
- Clear codes, attempt remote unlock while monitoring the BCM unlock output voltage/waveform.
- Visually inspect the entire unlock circuit wiring from BCM to door actuators and connectors for abrasion, pinched spots, melted insulation, or corrosion.
- With battery disconnected, perform continuity/resistance check between the unlock output conductor and battery positive. A near-zero reading indicates a short to B+.
- Disconnect the unlock actuator(s) and any intermediate connectors; re-check if the code returns when performing unlock command. If code clears, suspect actuator or wiring in that branch.
- Check unlock relay (if fitted): remove and bench-test for stuck contacts or substitute known-good relay.
- If short persists with actuators disconnected, trace wiring harness and isolate sections using back-probing and a fused jumper to locate the shorted segment.
- Repair damaged wiring or connectors; replace faulty actuator or relay as required.
- If wiring and external components test good, suspect BCM output transistor failure—verify with manufacturer procedures and consider module replacement or reprogramming per service manual.
- After repair, clear codes and perform full function test (multiple lock/unlock cycles, power off soak) to confirm repair and no battery drain.
Likely causes
- Pinched or chafed unlock wire contacting a constant 12V source
- Failed remote unlock relay stuck closed
- Door actuator motor shorted, connecting output directly to battery
- Water intrusion at connector forcing a positive feed
- Incorrectly installed aftermarket remote or alarm harness
Fault status
Status
Remote unlock circuit short to positive detected. Unlock function may be disabled, fuses may blow, or battery drain may occur. Inspect wiring, actuator, relays, and BCM.
Repair difficulty: Medium
Diagnostic time: 0.5-2.5 hours
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Code
B1525
MITSUBISHI
B — Body
DR.buckle SW SHT.to GND for N.O
Views:
UK: 7
EN: 13
RU: 12
AI status
Completed
Completed
100%
Causes
- Shorted unlock output wire to battery positive (B+)
- Stuck or welded relay contact feeding the unlock output
- Faulty door lock actuator with internal short
- Corroded or damaged connector causing high voltage feed into output
- Body Control Module (BCM) internal fault
- Aftermarket alarm/keyless entry wiring error
Symptoms
- Remote/key fob unlock does not work or works intermittently
- Fuse for locks blows repeatedly
- Continuous battery drain when vehicle is off
- Door(s) lock/unlock behave erratically or lock/unlock without command
- Relevant BCM warnings or multiple body system faults stored
What to check
- Read BCM/Body module codes and freeze frame data with a proper scan tool
- Visually inspect wiring harnesses, connectors, and door actuator(s) for damage or corrosion
- Check related fuses and relays for continuity and signs of melting or failure
- Measure voltage at the unlock output terminal with ignition off and while pressing remote
- Disconnect the door actuator/unlock motor and try the unlock command to see if code clears
- Inspect for aftermarket alarm or keyless entry modules and their wiring
Signal parameters
- Normal idle: unlock output = open/high-impedance (no battery feed)
- On unlock command: output expected = switched 12 V pulse (typically 0–1 A depending on actuator)
- Fault condition: persistent ~12 V present at output when command not given (short to B+)
- Resistance of unlock output to battery positive should be high (open); near 0 Ω indicates short
Diagnostic algorithm
- Connect a diagnostic scan tool, confirm B1525 and note any related codes or freeze-frame data.
- Clear codes, attempt remote unlock while monitoring the BCM unlock output voltage/waveform.
- Visually inspect the entire unlock circuit wiring from BCM to door actuators and connectors for abrasion, pinched spots, melted insulation, or corrosion.
- With battery disconnected, perform continuity/resistance check between the unlock output conductor and battery positive. A near-zero reading indicates a short to B+.
- Disconnect the unlock actuator(s) and any intermediate connectors; re-check if the code returns when performing unlock command. If code clears, suspect actuator or wiring in that branch.
- Check unlock relay (if fitted): remove and bench-test for stuck contacts or substitute known-good relay.
- If short persists with actuators disconnected, trace wiring harness and isolate sections using back-probing and a fused jumper to locate the shorted segment.
- Repair damaged wiring or connectors; replace faulty actuator or relay as required.
- If wiring and external components test good, suspect BCM output transistor failure—verify with manufacturer procedures and consider module replacement or reprogramming per service manual.
- After repair, clear codes and perform full function test (multiple lock/unlock cycles, power off soak) to confirm repair and no battery drain.
Likely causes
- Pinched or chafed unlock wire contacting a constant 12V source
- Failed remote unlock relay stuck closed
- Door actuator motor shorted, connecting output directly to battery
- Water intrusion at connector forcing a positive feed
- Incorrectly installed aftermarket remote or alarm harness
Fault status
Status
Remote unlock circuit short to positive detected. Unlock function may be disabled, fuses may blow, or battery drain may occur. Inspect wiring, actuator, relays, and BCM.
Repair difficulty: Medium
Diagnostic time: 0.5-2.5 hours
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Code
B1525
Other
B — Body
Keyless Entry Circuit Short To Battery
Views:
UK: 17
EN: 34
RU: 31
AI status
Completed
Completed
100%
Causes
- Shorted unlock output wire to battery positive (B+)
- Stuck or welded relay contact feeding the unlock output
- Faulty door lock actuator with internal short
- Corroded or damaged connector causing high voltage feed into output
- Body Control Module (BCM) internal fault
- Aftermarket alarm/keyless entry wiring error
Symptoms
- Remote/key fob unlock does not work or works intermittently
- Fuse for locks blows repeatedly
- Continuous battery drain when vehicle is off
- Door(s) lock/unlock behave erratically or lock/unlock without command
- Relevant BCM warnings or multiple body system faults stored
What to check
- Read BCM/Body module codes and freeze frame data with a proper scan tool
- Visually inspect wiring harnesses, connectors, and door actuator(s) for damage or corrosion
- Check related fuses and relays for continuity and signs of melting or failure
- Measure voltage at the unlock output terminal with ignition off and while pressing remote
- Disconnect the door actuator/unlock motor and try the unlock command to see if code clears
- Inspect for aftermarket alarm or keyless entry modules and their wiring
Signal parameters
- Normal idle: unlock output = open/high-impedance (no battery feed)
- On unlock command: output expected = switched 12 V pulse (typically 0–1 A depending on actuator)
- Fault condition: persistent ~12 V present at output when command not given (short to B+)
- Resistance of unlock output to battery positive should be high (open); near 0 Ω indicates short
Diagnostic algorithm
- Connect a diagnostic scan tool, confirm B1525 and note any related codes or freeze-frame data.
- Clear codes, attempt remote unlock while monitoring the BCM unlock output voltage/waveform.
- Visually inspect the entire unlock circuit wiring from BCM to door actuators and connectors for abrasion, pinched spots, melted insulation, or corrosion.
- With battery disconnected, perform continuity/resistance check between the unlock output conductor and battery positive. A near-zero reading indicates a short to B+.
- Disconnect the unlock actuator(s) and any intermediate connectors; re-check if the code returns when performing unlock command. If code clears, suspect actuator or wiring in that branch.
- Check unlock relay (if fitted): remove and bench-test for stuck contacts or substitute known-good relay.
- If short persists with actuators disconnected, trace wiring harness and isolate sections using back-probing and a fused jumper to locate the shorted segment.
- Repair damaged wiring or connectors; replace faulty actuator or relay as required.
- If wiring and external components test good, suspect BCM output transistor failure—verify with manufacturer procedures and consider module replacement or reprogramming per service manual.
- After repair, clear codes and perform full function test (multiple lock/unlock cycles, power off soak) to confirm repair and no battery drain.
Likely causes
- Pinched or chafed unlock wire contacting a constant 12V source
- Failed remote unlock relay stuck closed
- Door actuator motor shorted, connecting output directly to battery
- Water intrusion at connector forcing a positive feed
- Incorrectly installed aftermarket remote or alarm harness
Fault status
Status
Remote unlock circuit short to positive detected. Unlock function may be disabled, fuses may blow, or battery drain may occur. Inspect wiring, actuator, relays, and BCM.
Repair difficulty: Medium
Diagnostic time: 0.5-2.5 hours
Similar codes
Your experience will help others
+100 karma for a short comment :)
Was this AI description helpful?
Your feedback helps improve AI descriptions.
👍 Like
0
👎 Dislike
0
Send to email