B0135
Door Ajar Switch Circuit - Left Rear
Lowsensor
Overview
The B0135 diagnostic trouble code indicates that the body control module has identified a door ajar switch circuit - left rear issue. This code means a body sensor or its circuit is not providing expected readings. Accurate sensor data is important for proper operation of safety and convenience systems throughout the vehicle.
Symptoms
- Ambient light sensor not adjusting headlights
- Convertible top position incorrectly detected
- Airbag warning light on
- Seat occupancy sensor showing incorrect status
Common Causes
- Door ajar switch stuck or misaligned
- Physical obstruction blocking sensor
- Camera lens obstructed or damaged
- Seat weight sensor pad worn or damaged
Diagnosis Steps
- 1Connect an OBD-II scanner and read all stored body control module trouble codes
- 2Inspect the affected sensor and its wiring connector for damage or corrosion
- 3Test the sensor resistance or voltage output with a multimeter
- 4Check for physical obstructions, contamination, or misalignment of the sensor
- 5Verify sensor calibration using scan tool where applicable
Estimated Repair Cost
$50 — $400
Cost varies by vehicle, location, and repair shop. Includes parts and labor.
Commonly Affected Vehicles
Nissan PathfinderSubaru ForesterChevrolet EquinoxFord Escape
Related Codes
More Sensor Codes
P0070Ambient Air Temperature Sensor Circuit
LowP0071Ambient Air Temperature Sensor Range/Performance
LowP0072Ambient Air Temperature Sensor Circuit Low
LowP0073Ambient Air Temperature Sensor Circuit High
LowP0074Ambient Air Temperature Sensor Circuit Intermittent
LowP0095Intake Air Temperature Sensor 2 Circuit
LowFrequently Asked Questions
A stuck or misaligned door ajar switch is the most common cause. The switch is located in the door latch mechanism and can be cleaned or replaced for $20-$100.