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B0131 — Av Sensor Washer Fluid C Control Circuit

Generic OBD-II · all makesBody

B0131 is a body control module (BCM) fault code indicating an electrical problem with the washer fluid level sensor or washer pump circuit (Circuit C). This code is set when the BCM detects an open, short, or invalid signal from the washer fluid system monitoring circuit.

Symptoms

What causes it — most likely first

1. Failed washer fluid level sensor

The sensor inside the washer fluid reservoir has failed or developed internal corrosion, causing an open circuit or invalid signal to the BCM.

2. Damaged or corroded wiring harness

Wiring to the washer fluid sensor has been damaged by chafing, road debris, or water intrusion, creating an open or short circuit.

3. Loose or corroded electrical connector

The connector at the washer fluid reservoir sensor has poor pins, corrosion, or is not fully seated, interrupting the signal.

4. Washer fluid pump failure

In systems with a dedicated pump for this circuit, the pump motor has failed or the pump wiring is damaged.

5. Blown fuse or failed relay

A blown fuse or faulty relay protecting the washer fluid circuit has caused loss of power to the sensor or pump.

6. Body Control Module (BCM) malfunction

The BCM itself has failed, though this is rare and should be diagnosed only after all other causes are ruled out.

How it's diagnosed

  1. Verify washer fluid level and add fluid if low - low fluid can sometimes cause sensor readings that trigger this code
  2. Locate the washer fluid level sensor connector and inspect for corrosion, damage, or loose pins
  3. Check the fuse for the washer system and replace if blown
  4. Inspect the wiring harness along the firewall and near the washer reservoir for damage or chafing
  5. Test the washer fluid level sensor with a multimeter for proper resistance values (refer to manufacturer specs)
  6. If equipped, test the washer pump motor for proper operation and ground connection
  7. As a last resort, check for BCM software updates or fault codes that might indicate BCM failure

Code facts & related codes

SystemBody
StandardizationSAE generic — identical on every make
Related codesB0129 — Dcac Converter High Voltage Power OutlB0130 — Av Sensor Washer Fluid B Control CircuB0132 — Av Sensor Washer Fluid D Control CircuB0133 — Av Sensor Washer Fluid E Control CircuB0134 — Av Sensor Washer Fluid F Control Circu

Vehicles this code applies to

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

1997 BMW 528I1997 BMW 540I

Frequently asked

Is B0131 a serious code that affects drivability?

No, this is a comfort and convenience code related to windshield washer function. It does not affect engine performance, transmission, or safety systems. You can drive normally, but will not have windshield washer functionality.

Do I need to replace the Body Control Module (BCM) to fix this code?

Almost never. The BCM is rarely the cause of B0131. In the vast majority of cases, the problem is the sensor, wiring, connectors, or washer pump. Replacing the BCM unnecessarily is one of the most common misdiagnoses for this code.

Can I still use my windshield wipers if this code is present?

Yes, windshield wipers operate completely independently from the washer fluid system. The wipers will function normally even with this fault code present.

Is this something I can diagnose and repair myself?

Basic diagnosis is DIY-friendly. Checking fluid level, fuses, and inspecting visible wiring and connectors can be done at home. Sensor and pump replacement are also straightforward repairs for most vehicle owners with basic tools.