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DTC codes / B01xx · Airbags, seats, doors, lights and comfort systems / B0109

B0109LIDAR Washer Actuator D

B0109 indicates that the body control module has detected a fault in the electrical circuit for the LIDAR (Light Detection and Ranging) washer actuator D, which is the small motor or pump responsible for cleaning the LIDAR sensor lens used by advanced driver assistance systems. The computer monitors the actuator's command signal and feedback circuit and sets this code when the expected current or voltage does not match the commanded state.

SystemBody
Code typeGeneric (all makes)
SeverityLow
Fix difficultyIntermediate
AreaAirbags, seats, doors, lights and comfort systems

Symptoms you may notice

  • Illumination of the LIDAR or driver assistance system warning light on the dashboard
  • A message on the driver information center stating that the LIDAR sensor is blocked or the washer system is unavailable
  • The LIDAR washer may fail to spray fluid when activated, leaving the sensor lens dirty
  • The washer pump may run continuously or not at all, depending on the failure mode
  • Often no symptoms besides the warning light, especially if the actuator fails only intermittently
  • Other driver assistance features such as adaptive cruise control or lane keeping may be disabled as a consequence

Common causes, most likely first

  1. A failed LIDAR washer actuator motor or pump, typically due to internal wear or corrosion
  2. Damaged or disconnected wiring harness at the actuator connector, often from road debris or vibration
  3. Corroded or loose electrical terminals in the actuator circuit
  4. A blown fuse that supplies power to the washer actuator circuit
  5. A faulty body control module or driver module that commands the actuator
  6. A blocked or frozen washer nozzle or hose that overloads the actuator and triggers the code
  7. Water intrusion into the actuator connector or module causing a short or open circuit

How to diagnose and fix it

  1. Verify the code with a scan tool and check for any related body or driver assistance codes that might indicate a shared circuit fault
  2. Inspect the LIDAR washer actuator connector and wiring for corrosion, damage, or loose pins, and clean or repair as needed
  3. Check the fuse that protects the washer actuator circuit and replace it if blown, then recheck for the code
  4. Test the actuator with a bidirectional scan tool or by applying power and ground directly to confirm whether it operates
  5. Measure resistance and voltage on the actuator control circuit to rule out an open or short in the harness
  6. If the actuator fails the functional test, replace it and clear the code, then verify the washer operates correctly
  7. If the circuit and actuator test good, diagnose the body control module or driver module for internal faults

LIDAR washer faults that fool technicians

  • A blocked washer nozzle or kinked hose can cause the actuator to draw excessive current and set B0109 even though the actuator itself is healthy, so always check for free flow before condemning the part.
  • The LIDAR washer actuator often shares a fuse or ground with other body components, so a blown fuse may disable multiple systems and the code may be a symptom rather than the root cause.
  • Intermittent codes can be caused by water intrusion into the actuator connector after car washes or heavy rain, which leaves no visible damage until the connector is opened and inspected.
  • Some vehicles require a recalibration or initialization of the driver assistance system after actuator replacement, and failing to perform that step can leave the warning light on even with a new part.
  • The code does not always mean the actuator is dead; a shorted or open control wire between the body control module and the actuator will set the same code and requires circuit testing rather than parts swapping.

Can I keep driving with B0109?

The vehicle remains safe to drive because the LIDAR washer only affects sensor cleaning and does not impair braking, steering, or throttle control, but you should avoid relying on driver assistance features that depend on a clean LIDAR lens until the fault is repaired. If the warning light is accompanied by other driver assistance failures, have the system checked promptly.

Tools that help

Tools we recommend are in the Auto Veteran shop on Amazon. As an Amazon Associate we earn from qualifying purchases.

Guidance is general and written for all OBD-II vehicles. Exact tests and values vary by model, so confirm the fault before replacing parts.

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