B011D: Fluid Reservoir Level Sensor B

What it means

The control module monitors the signal from fluid reservoir level sensor B to determine whether the monitored reservoir has sufficient fluid. It sets this code when the sensor signal is missing, out of range, or otherwise fails the module’s checks.

At a glance

• Usually lights the airbag (SRS) or body-system warning light

How it works

Sensor B is one of the level sensors used by the vehicle’s control module to assess fluid in a monitored reservoir. The module checks whether sensor B’s signal changes plausibly with the fluid level; this code sets when its signal is missing, outside the expected range, or fails an electrical check.

Common causes

Most likely first.

1. Failed reservoir level sensor or float
2. Open or shorted sensor wiring
3. Loose or corroded connector
4. Damaged reservoir or stuck float
5. Fault in the sensor input circuit

Symptoms

• Warning light or symbol related to the affected system
• Comfort or safety function impaired

How to diagnose it

1. Record freeze-frame data and read live data for sensor B, if available, to see whether its reported level is absent or implausible.
2. Identify which reservoir sensor B monitors using vehicle service information, then check that reservoir’s fluid level and look for leaks or damage.
3. Inspect sensor B’s float for binding and check its connector for looseness, corrosion, moisture, or pushed-back pins.
4. Follow sensor B’s wiring toward the control module and look for breaks, chafing, pinching, or contact with fluid.
5. With the circuit safely isolated as specified by the manufacturer, check for an open or short and compare sensor and input-circuit tests with the manufacturer’s specification.

Common fixes

• Correct the fluid level and repair any leak at the reservoir monitored by sensor B.
• Free a stuck float or repair damage that prevents sensor B from moving with the fluid level.
• Clean and secure sensor B’s connector, or repair damaged terminals.
• Repair an open or short in sensor B’s wiring.
• Replace the failed sensor B or repair the module input circuit if testing identifies it as the fault.

Can I keep driving?

The warning may be unreliable, so check the monitored fluid level before driving and do not rely on the related comfort or safety function. If the reservoir serves a critical system or its level is low, stop and address that condition before continuing.