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B0109 — Lidar Washer Actuator D

Generic OBD-II · all makesBody

The B0109 code indicates a malfunction in the Lidar Washer Actuator D circuit. This actuator sprays cleaning fluid onto the lidar sensor to maintain its performance, and the code sets when the control module detects an electrical fault such as an open, short, or mechanical failure.

Symptoms

What causes it — most likely first

1. Faulty Lidar Washer Actuator D

The actuator itself is defective, stuck, or has an internal electrical failure, preventing it from operating when commanded.

2. Open or short in the actuator wiring harness

Damaged, chafed, or broken wires between the control module and the actuator can cause an open circuit or a short to power/ground.

3. Poor electrical connection at the actuator connector

Corrosion, bent pins, or moisture in the connector can create high resistance or intermittent contact, triggering the code.

4. Blown fuse or faulty relay

A blown fuse or defective relay in the washer actuator power supply circuit will prevent the actuator from receiving voltage.

5. Faulty control module (e.g., body control module or ADAS module)

In rare cases, the module that controls the lidar washer may have an internal fault, but this is the least likely cause and should only be considered after all other possibilities are ruled out.

How it's diagnosed

  1. Use a scan tool to verify the B0109 code and check for any other related codes that may provide additional clues.
  2. Visually inspect the lidar washer actuator, its wiring harness, and connectors for obvious damage, corrosion, or disconnection.
  3. Check the washer fluid level and ensure the system is primed; a low fluid condition can sometimes cause erroneous codes.
  4. Command the actuator on with a scan tool; if it does not operate, test for power and ground at the actuator connector using a multimeter.
  5. If power and ground are present but the actuator does not work, replace the actuator. If power or ground is missing, trace the circuit back to the fuse, relay, and control module.
  6. After repairs, clear the code and perform a functional test of the lidar washer system to confirm the fix.

Code facts & related codes

SystemBody
StandardizationSAE generic — identical on every make
Related codesB0100 — Sensor Cleaning Air Blower ActuatorB0101 — Sensor Cleaning Air Blower Actuator BB0102 — Sensor Cleaning Air Blower Actuator CoB0103 — Sensor Cleaning Air Blower Actuator B B0104 — Sensor Cleaning Air Blower Actuator CoB0105 — Sensor Cleaning Air Blower Actuator B

Vehicles this code applies to

The definition is universal; the diagnostics are engine-specific. Open your vehicle for the codes documented for it:

2013 BMW 135I Coupe2013 BMW 135I Convertible

Frequently asked

What does the B0109 code mean?

It means the control module has detected a malfunction in the circuit for the lidar washer actuator D, which cleans the lidar sensor used for driver assistance systems.

Can I still drive with this code?

Yes, the vehicle is drivable, but the lidar sensor may become dirty and affect features like adaptive cruise control or automatic emergency braking. It's best to repair it promptly.

Is the engine computer (PCM) the cause of this code?

No, the PCM is almost never the cause. This is a body or chassis code, typically set by a body control module or ADAS module. The fault is usually in the actuator, wiring, or power supply.

How do I fix B0109?

Start by checking fuses, wiring, and connectors. If those are good, test the actuator itself. In most cases, replacing the lidar washer actuator resolves the issue.