What Does B1835 Mean?
This code indicates the Body Control Module (BCM) has detected an open circuit in the door unlock disarm output circuit, which controls the security system disarm function when doors are unlocked. The BCM monitors this circuit and sets this code when it cannot complete the electrical path to the door lock actuator or security system interface. This prevents proper communication between the door unlock mechanism and the vehicle's anti-theft system.
Common Causes
40%
Broken or corroded wiring between BCM and door lock actuator or security module
30%
Faulty door lock actuator with internal open circuit
20%
Failed BCM door unlock output driver circuit
10%
Damaged or corroded ground connection for door lock circuit
Diagnostic Steps
1
Step 1: Perform visual inspection of door lock actuator connectors and wiring harness from BCM to all door lock actuators, checking for damaged wires, corroded terminals, loose connections, or water intrusion in connector boots
2
Step 2: Using a digital multimeter, backprobe the BCM connector at the door unlock output pin and measure resistance to the door lock actuator connector terminal with ignition off (should read typical actuator coil resistance, usually 2-8 ohms, not infinite/open)
3
Step 3: Check for voltage at the door lock actuator connector while commanding door unlock function through scan tool active tests or manual door unlock switch operation (should see battery voltage or switched ground depending on system design)
4
Step 4: If no voltage present at actuator during unlock command, trace wiring back toward BCM checking for breaks or opens using continuity testing with harness disconnected
5
Step 5: Test suspected door lock actuator by applying direct power and ground to verify mechanical operation, replace if actuator shows open circuit resistance or fails to operate
6
Step 6: After repairs, clear codes, operate door locks through multiple cycles using key fob and manual switches, verify security system disarms properly and code does not return
Estimated Repair Cost
$150 - $600
Parts + labor, varies by vehicle and location
This code indicates the Body Control Module (BCM) has detected an open circuit in the door unlock disarm output circuit, which controls the security system disarm function when doors are unlocked. The BCM monitors this circuit and sets this code when it cannot complete the electrical path to the doo...
The most common cause of B1835 (Door Unlock Disarm Output Circuit Open) is: Broken or corroded wiring between BCM and door lock actuator or security module
Typical repair costs for B1835 range from $150 to $600, depending on the vehicle, location, and whether you do it yourself or go to a shop.
Safe to continue driving as this affects convenience and security features only. The vehicle may not disarm the security system properly when unlocking doors, potentially causing alarm activation or remote start issues, but does not impact vehicle operation or safety systems.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to B1835 to identify the root cause.
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Quick Info
Category
Body
System
Body Control and Security System
Difficulty
Type
Manufacturer
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