OBD Code B1560: Door Unlock Motor Circuit Malfunction

If your vehicle has triggered the B1560 diagnostic trouble code, it means the onboard diagnostic system has detected a problem with the door unlock motor circuit. This body code affects your vehicle’s power door lock system and can prevent doors from unlocking electronically. Understanding what this code means and how to address it will help you restore your door lock functionality and ensure your vehicle’s security features work as intended.

What Does Code B1560 Mean?

Code B1560 is a body system diagnostic trouble code that specifically indicates a malfunction in the door unlock motor circuit. The “B” prefix identifies this as a body system code (as opposed to powertrain or chassis codes), and the code points to the electrical circuit responsible for operating the door unlock motors.

Your vehicle’s power door lock system uses electric motors (actuators) to lock and unlock the doors. These motors are controlled by a central door lock module or body control module (BCM) that receives signals from your key fob, door lock switches, or the vehicle’s security system. When the B1560 code is triggered, it means the diagnostic system has detected an electrical fault in this circuit—such as a broken connection, faulty motor, or control module issue.

This code can affect one door or multiple doors, depending on the circuit configuration and the nature of the fault. Some vehicles have individual unlock motors for each door, while others use a shared circuit.

Common Symptoms

• Doors won’t unlock electronically: The most obvious symptom—pressing the unlock button on your key fob or door panel doesn’t unlock the doors
• Intermittent unlock function: Doors unlock sometimes but not consistently, indicating a loose connection or failing motor
• One or more doors affected: Only specific doors fail to unlock while others work normally
• Clicking sound from door: You hear a clicking or buzzing noise from the door lock area when attempting to unlock, suggesting the motor is receiving power but not functioning
• Check Engine or warning light: The diagnostic trouble code triggers a warning light on your dashboard
• Manual unlock still works: You can still unlock doors manually with the key, but electronic unlocking fails
• No response to key fob: The key fob’s unlock button has no effect on the door locks
• Doors lock but won’t unlock: The locking function may work while unlocking fails, or vice versa

Possible Causes

Listed from most to least common:

1. Faulty door lock actuator/motor: The electric motor that physically moves the lock mechanism has failed or is worn out. This is the most common cause of B1560 codes.
2. Corroded or damaged wiring harness: The electrical connectors and wires leading to the door lock motor have corrosion, water damage, or broken connections, preventing proper signal transmission.
3. Loose or corroded electrical connectors: Connection points at the door lock motor, door latch, or control module are loose, corroded, or improperly seated.
4. Blown fuse or faulty relay: The fuse protecting the door lock circuit has blown, or the relay controlling the circuit is defective.
5. Body Control Module (BCM) malfunction: The central computer controlling the door locks is faulty and not sending proper signals to the unlock motors.
6. Door lock switch failure: The interior door lock switch (the button you press to lock/unlock) is broken or not sending the correct signal.
7. Key fob transmitter issue: Your key fob’s unlock button is broken or the fob isn’t transmitting the unlock signal properly.
8. Water intrusion in door panel: Moisture has entered the door, corroding the motor or electrical connections.
9. Broken door latch mechanism: While not strictly a motor circuit issue, a broken latch can prevent proper unlock operation and trigger this code.

Diagnostic Steps

Follow these steps to diagnose the B1560 code:

Step 1: Check for Additional Codes

Use an OBD-II scanner to read all stored and pending codes. Multiple related codes (such as B1561, B1562, etc.) may point to a broader issue with the door lock system or control module.

Step 2: Test Manual Unlock Function

Try unlocking the affected door(s) manually with your key. If manual unlock works, the problem is in the electronic circuit, not the mechanical lock. If manual unlock also fails, the issue may be mechanical.

Step 3: Test Key Fob and Door Lock Switches

Attempt to unlock the doors using:

• The key fob unlock button
• The interior door lock switch
• The exterior door handle (if your vehicle has power unlock via handle)

Note which methods work and which don’t—this helps pinpoint whether the problem is in the fob, switch, or motor circuit.

Step 4: Inspect Wiring and Connectors

Locate the door lock actuator connector (typically found inside the door panel). Inspect for:

• Corrosion or green/white oxidation on connector pins
• Water damage or moisture inside the connector
• Loose or bent pins
• Damaged wiring insulation

Clean corroded connectors with electrical contact cleaner and a small brush, then reseat firmly.

Step 5: Check the Door Lock Fuse and Relay

Consult your vehicle’s fuse box diagram (typically found in the owner’s manual or on the fuse box cover). Locate and inspect the door lock fuse and relay. Look for:

• A blown fuse (broken wire inside the fuse)
• A burnt or damaged relay

Replace if necessary. If the fuse blows again immediately, there’s a short circuit in the system.

Step 6: Test the Door Lock Actuator

With the door panel removed, you can test the actuator directly:

• Apply 12V power directly to the actuator terminals using jumper cables connected to the battery
• Observe whether the motor moves or makes any sound
• If there’s no response, the motor is likely faulty
• If it responds, the motor is functional and the problem lies in the control circuit

Step 7: Use a Multimeter to Test Voltage

With the door panel removed and the ignition on:

• Test for 12V power at the actuator connector when the unlock button is pressed
• If voltage is present but the motor doesn’t work, the motor is faulty
• If no voltage is present, the problem is in the wiring, switch, or control module

Step 8: Consult the Body Control Module

If all previous tests pass but the code persists, the BCM may be faulty. This typically requires professional diagnostic equipment and may necessitate BCM reprogramming or replacement.

Repair Cost Estimates

Repair costs for B1560 vary widely depending on the root cause:

• Fuse or relay replacement: $50–$150 (parts and labor)
• Connector cleaning and repair: $75–$200
• Door lock actuator replacement: $200–$600 per door (parts and labor vary by vehicle make/model)
• Wiring harness repair or replacement: $300–$800 depending on extent of damage
• Door lock switch replacement: $150–$400
• Body Control Module (BCM) replacement: $800–$2,000+ (including programming)
• Key fob replacement: $100–$300

Most B1560 codes are resolved with actuator replacement or connector cleaning, typically costing $200–$600. Professional diagnostic fees may add $100–$150 if you choose to have a technician diagnose the issue.

Can I Still Drive?

Severity: Moderate to Low (depending on circumstances)

A B1560 code does not affect your vehicle’s ability to start, run, or drive safely. However, it does impact your security and convenience:

• Safety concern: If you cannot unlock your doors electronically, you may be unable to exit the vehicle quickly in an emergency. Always ensure you can unlock doors manually with your key.
• Security concern: If the unlock circuit is malfunctioning, the lock circuit may also be affected, potentially leaving your vehicle unsecured.
• Convenience: You’ll lose the convenience of electronic unlocking via key fob or door switches.

Recommendation: You can continue driving, but address the issue promptly. At minimum, verify that manual unlock works on all doors so you can exit safely. If multiple doors are affected or you suspect a security issue, have the vehicle serviced as soon as possible.

Frequently Asked Questions