The P0558: Brake Booster Pressure Sensor Circuit High code indicates that the engine control module (ECM) has detected a higher-than-expected voltage or signal from the brake booster pressure sensor. This sensor monitors the pressure inside the brake booster, which is essential for providing proper brake assist during braking.
P0558 – Quick Overview
| Code | Information |
|---|---|
| Meaning | P0558: Brake Booster Pressure Sensor Circuit High |
| Is it serious? | Yes, as it can affect braking performance, potentially reducing safety. |
| Possible causes | – Faulty brake booster pressure sensor – High brake booster pressure – Wiring issues |
| How to diagnose? | – Test the brake booster pressure sensor – Check brake booster pressure – Inspect wiring for faults |
P0558 Meaning
The P0558: Brake Booster Pressure Sensor Circuit High code is triggered when the ECM detects that the brake booster pressure sensor is sending a higher-than-expected signal. This may result from an issue with the sensor itself, abnormally high brake booster pressure, or faulty wiring. High pressure in the brake booster can affect braking performance, potentially leading to hard braking or a lack of brake assist.
Step-by-step diagnostic guide
| Action | Description | Tools Needed |
|---|---|---|
| Check for Other Codes | Use an OBD-II scanner to check for related fault codes that could provide more information about the brake system issue. | OBD-II Scanner |
| Test the Brake Booster Pressure Sensor | Use a multimeter to measure the voltage output from the brake booster pressure sensor. Compare the readings to manufacturer specifications to determine if the sensor is functioning properly. | Multimeter, Diagnostic Tool |
| Check Brake Booster Pressure | Use a vacuum gauge to measure the pressure inside the brake booster. If pressure is abnormally high, inspect for potential mechanical issues like blockages or malfunctioning components. | Vacuum Gauge, Basic Tools |
| Inspect Wiring for Faults | Visually inspect the wiring and connectors for the brake booster pressure sensor. Look for signs of damage, loose connections, or corrosion that could cause incorrect signals. | Flashlight, Multimeter |
| Clear the Code and Test Drive | After performing repairs, clear the code using an OBD-II scanner and take the vehicle for a test drive to ensure the brake booster and sensor function correctly. | OBD-II Scanner, Vehicle Manual |
| Recheck for Codes | Re-scan the vehicle after the test drive to ensure that the P0558 code hasn’t returned. | OBD-II Scanner |
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