The brake fluid level sensor is sending a constant ground signal to the ECU, like a light switch stuck in the "on" position. The ECU can't tell if the brake fluid is actually low or high because the sensor wire is shorted.
The ECU monitors the brake fluid level sensor's voltage signal, which should vary between high and low states. When a short to ground occurs, the sensor voltage remains near 0V continuously, preventing the ECU from detecting normal fluid level changes. The ECU interprets this constant low signal as a sensor malfunction rather than an actual low fluid condition.
| Parameter | Normal Range | Fault Condition |
|---|---|---|
| Sensor Voltage | 0.5V to 4.5V (varying with fluid level) | Stuck at 0V or below 0.2V |
| Signal Continuity | Alternating high/low states | No state change detected |