Low fluid level in the reservoir, which is the most common and simplest cause; Faulty fluid level sensor (internal resistance drift or stuck float); Damaged or corroded wiring harness or connector at the sensor; Open or short circuit in the sensor signal or ground circuit; Failed body control module (BCM) or fluid level control module; Contaminated fluid causing the float to stick or the sensor to misread; Aftermarket or incorrect fluid cap interfering with the sensor

DTC codes / B01xx · Airbags, seats, doors, lights and comfort systems / B011E

B011EFluid Reservoir Level Sensor C

Q: What does code B011E mean?

Fluid Reservoir Level Sensor C. B011E indicates that the body control module (BCM) or dedicated control module has detected a fault in the circuit for the fluid reservoir level sensor designated as 'C'. This sensor typically monitors the level of a fluid such as washer fluid, coolant, or brake fluid, and the code is set when the module receives an out-of-range voltage or a signal that does not correlate with expected values.

B011E indicates that the body control module (BCM) or dedicated control module has detected a fault in the circuit for the fluid reservoir level sensor designated as 'C'. This sensor typically monitors the level of a fluid such as washer fluid, coolant, or brake fluid, and the code is set when the module receives an out-of-range voltage or a signal that does not correlate with expected values.

SystemBody

Code typeGeneric (all makes)

SeverityLow

Fix difficultyIntermediate

AreaAirbags, seats, doors, lights and comfort systems

Symptoms you may notice

Illumination of the fluid level warning light on the dashboard
A message on the driver information center indicating low fluid level, even when the reservoir is full
Intermittent or flickering warning light as the vehicle goes over bumps or around corners
Often no symptoms besides the warning light, with no drivability issues
If the sensor is for brake fluid, a red brake warning light may appear, but the pedal feel remains normal
If the sensor is for coolant, the temperature gauge may still read normal, but the low coolant light stays on

Common causes, most likely first

Low fluid level in the reservoir, which is the most common and simplest cause
Faulty fluid level sensor (internal resistance drift or stuck float)
Damaged or corroded wiring harness or connector at the sensor
Open or short circuit in the sensor signal or ground circuit
Failed body control module (BCM) or fluid level control module
Contaminated fluid causing the float to stick or the sensor to misread
Aftermarket or incorrect fluid cap interfering with the sensor

How to diagnose and fix it

Check the fluid level in the reservoir and top up if low; inspect for leaks if the level is repeatedly low
Inspect the sensor connector and wiring for corrosion, damage, or loose pins
Measure the sensor resistance or voltage output and compare to specifications; replace the sensor if out of range
Check the sensor ground circuit for continuity to chassis ground
Check for short to voltage or short to ground on the signal circuit
If the circuit tests good, verify the module's ability to read the sensor by using a scan tool to monitor live data
Replace the body control module only after confirming all wiring and sensor inputs are correct and performing necessary programming

Before you replace the fluid level sensor

A low fluid level is the most frequent trigger for B011E, so always verify the reservoir level before condemning the sensor.
The sensor may be part of a combined washer fluid and coolant level switch on some vehicles, and a failure in one section can set codes for multiple fluids.
Corrosion at the sensor connector is a common hidden cause, especially on vehicles driven in winter road salt conditions.
The code can be set by a faulty ground connection at the sensor or at the module, which is often overlooked during diagnosis.
After replacing the sensor or module, some vehicles require a relearn or calibration procedure to clear the code and restore accurate level readings.

Can I keep driving with B011E?

The vehicle is generally safe to drive with B011E because it does not affect engine operation or safety systems, but you should verify the actual fluid level manually to avoid overlooking a genuine low-fluid condition that could lead to component damage. Avoid ignoring a red brake warning light if the sensor is for brake fluid, as that could indicate a serious safety issue.

Tools that help

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