Severity Medium
B1835

Driver Door Unlock/Disarm Circuit Open

📅 Last reviewed: July 2026
What does the B1835 code mean?

The Body Control Module (BCM) or Central Security Module has detected an open circuit in the driver door unlock/disarm output. This circuit controls the door lock actuator or lock cylinder switch to disarm the anti-theft system and unlock the doors. The fault indicates that the control signal is not reaching its destination due to a break in the wiring or a failed component.

Medium
Severity
Variable
Typical Cost
Medium
Frequency

1. Commonly Affected Makes

FordLincolnMercury

2. Most Common Causes

3. Symptoms You Will Notice

4. Step-by-Step Diagnosis

1

Check for broken or damaged wires in the driver door harness, especially at the hinge area.

2

Inspect connectors at the BCM and driver door for corrosion, bent pins, or poor contact.

3

Test the driver door lock actuator and lock cylinder switch for continuity and proper operation.

4

If all wiring and components check out, suspect a faulty BCM and perform a module self-test or replacement.

5. Frequently Asked Questions

Is it safe to drive?

Yes, the vehicle is generally safe to drive, but you may experience inconvenience with door locking/unlocking and the anti-theft system. It is recommended to repair the issue to ensure full functionality.

How much does it cost to fix?

Repair costs typically range from $100 to $400, depending on whether the issue is a simple wiring repair, a connector replacement, or a BCM replacement.

6. Related Codes

Need an OBD2 Scanner for the B1835? Compare the best scanners compatible with all vehicles
🛒 View OBD2 Scanners →