B0120 code meaning
Fluid Reservoir Level Sensor E
What B0120 means
B0120 relates to level sensor E. Ford's application US20190265715A1 describes a container for sensor cleaning whose level sensor measures conductance at a fixed height: air gives a resistance above roughly 1000 ohms, the slightly conductive fluid one below it. Because the fluid moves with the car, the computer filters the signal with acceleration and yaw rate, then estimates the remaining volume from pump activity, and it suspects a leak if the level falls while no washing is requested, in which case the vehicle may be routed to a service centre. Ford's patent US10569746B2 puts such a container on the roof beside the lidar. Letter E is not tied publicly to any tank, and no manufacturer documents B0120. Without the signal, remaining fluid can only be guessed.
B0120 at a glance
- Check engine lightUsually not
- Emissions testNot an emissions code
- Limp modeNot expected
- Repair difficultyMedium, DIY possible
- Typical labor0.3 to 2 hours
- Clears after repairWhen cleared with a scanner
Symptoms of B0120
- Refill warning too early, too late or constantly on
- Cleaning of exterior sensors may be restricted
Common causes of B0120
- Most likelyElectrodes fouled or fluid with unsuitable conductivity (e.g. plain distilled water)
- PossibleOpen or short in the sensor circuit
- Less likelyLeaking reservoir or hose making the level drop unexpectedly
Check the most likely causes first. Replacing parts by guesswork is the most expensive way to clear a code.
Parts involved
Fluid reservoir level sensor eSensor wiring
What each part of B0120 means
| B | Body system: airbags, seat belts, power seats, lights and climate control. |
| 0 | Generic code: it means the same on every make (SAE standard). |
| 20 | The exact fault in that area. |
What to do next
- Note B0120 and any other codes stored with it: several codes together often point to one cause.
- Check for loose connectors and damaged wiring around the parts the code names.
- Check open recalls for your car: some faults are fixed for free by the dealer. Enter your VIN.
- Clear the code only after the repair. If it comes back, the fault is still there.
Buying a used car? Scan it for stored codes before you pay. A recently cleared memory can hide a problem.
Questions about B0120
What does B0120 mean?
B0120 means "Fluid Reservoir Level Sensor E". B0120 relates to level sensor E. It is a generic code, so it means the same on every make.
Is it safe to drive with B0120?
B0120 does not normally turn on the check engine light by itself. Watch for the symptoms above and have it checked soon.
Will B0120 fail an emissions test?
B0120 is not an emissions code, so on its own it usually does not fail an emissions test. Other stored codes or a lit check engine light still can.
How hard is B0120 to fix?
Difficulty: medium. A typical repair takes 0.3 to 2 hours of work. A careful DIY repair is possible with basic tools and a scanner.
Will B0120 clear itself after the repair?
Clear the code with a scanner after the repair. If the fault is fixed, it does not come back.