Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
Normal Operation and Fault Conditions
The brake booster vacuum sensor receives a sensor supply voltage of 5 volts from the ABS module. The sensor is also grounded through the ABS module. The sensor uses the pressure differential between the atmosphere and the brake booster vacuum chamber to produce a return voltage signal to the ABS module between 0.2 volt and 4.9 volts. The ABS module uses other sensor inputs such as wheel speed, brake pedal and stability sensors to determine if the vehicle is stopping and at what rate of deceleration. This information is compared against the vacuum pressure sensor to determine the validity of the sensor signal and the working condition of the sensor itself.
| DTC | Description | Fault Trigger Conditions |
|---|---|---|
| P0555 | Brake Booster Pressure Sensor Circuit | This DTC sets due to differences between the brake booster mounted vacuum sensor signal and the PCM calculated vacuum level. This DTC does not illuminate any warning indicators nor are there any associated service messages. |
| P0556 | Brake Booster Pressure Sensor Circuit Range/Performance | This DTC sets due to differences between the brake booster mounted vacuum sensor signal and the PCM calculated vacuum level. This DTC does not illuminate any warning indicators nor are there any associated service messages. |
| P0557 | Brake Booster Pressure Sensor Circuit Low | This DTC sets due to differences between the brake booster mounted vacuum sensor signal and the PCM calculated vacuum level. This DTC does not illuminate any warning indicators nor are there any associated service messages. |
| P0558 | Brake Booster Pressure Sensor Circuit High | This DTC sets due to differences between the brake booster mounted vacuum sensor signal and the PCM calculated vacuum level. This DTC does not illuminate any warning indicators nor are there any associated service messages. |
| P0559 | Brake Booster Pressure Sensor Circuit Intermittent | This DTC sets due to differences between the brake booster mounted vacuum sensor signal and the PCM calculated vacuum level. This DTC does not illuminate any warning indicators nor are there any associated service messages. |
| P05FF | Brake Pressure Sensor/Brake Pedal Position Sensor Correlation | This DTC sets if the information from the brake pressure sensor and brake pedal position sensor do not match. This is most likely due to sensor concerns, wiring harness concerns or vehicle communication concerns. |
NO RELATED
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.