Technical Description of OBD-II Trouble Code
The circuit for the Brake Booster Pressure Sensor is experiencing intermittent issues.
What does that mean?
This is a generic diagnostic trouble code (DTC) for powertrain and applies to OBD-II vehicles equipped with a brake booster pressure sensor. This includes vehicles from various manufacturers such as Fiat, Alfa Romeo, Nissan, Ford, Dodge, Pontiac, Chevrolet, Acura, Subaru, Hyundai, etc. Although it is a generic code, the specific repair steps may vary depending on the year, make, model, and powertrain configuration of the vehicle.
Trouble code P0559 is one of several possible codes related to the Brake Booster Pressure Sensor Circuit.
This code indicates that the Powertrain Control Module (PCM) has detected a malfunction that is affecting the operation of the brake booster pressure sensor circuit. The codes commonly associated with brake booster pressure sensor circuit malfunctions are P0555, P0556, P0557, P0558, and P0559. The specific code activated by the PCM and the brake warning light will illuminate or flash when braking, depending on the situation.
The purpose of the brake booster pressure sensor circuit is to monitor the amount of pressure (vacuum) applied to the power brake booster. The PCM controls the circuit to adapt to different braking situations and adjust the pressure to assist with brake pedal operation. This process is crucial for the proper functioning of power brakes and for safely slowing down or stopping the vehicle with minimal foot pressure on the brake pedal.
Code P0559 is set by the PCM when there is an intermittent output voltage signal problem in the brake booster pressure sensor circuit.
What is the severity of this DTC?
The severity of this code varies depending on the specific malfunction, and if not corrected in a timely manner, the severity level will increase. At some point, the safety of the vehicle could be compromised, requiring immediate attention.
Photo of a brake booster pressure (vacuum) sensor:
What are some of the symptoms of the code?
Symptoms of a P0559 trouble code may include:
What are some of the common causes of the code?
Causes for this P0559 code may include:
What are some P0559 troubleshooting steps?
The first step in the troubleshooting process for any malfunction is to research the Technical Service Bulletins for known issues with the specific vehicle.
Locate all of the components associated with the Brake Booster Pressure Sensor Circuit. This will include the brake booster pressure sensor, the brake booster, vacuum lines, wiring, connectors, and the PCM on a simplex system. Once these components are located, conduct a thorough visual inspection to check all of the associated wiring and connectors for obvious defects such as scraping, rubbing, bare wires, or burn spots. Also, examine the connectors for corrosion buildup or damaged pins. Inspect the vacuum lines for security, weather cracks, leaks, and overall serviceability.
Advanced Steps
The advanced steps are highly specific to the vehicle and require the appropriate advanced equipment for accurate performance. These procedures require a digital multimeter and the specific technical references for the vehicle. The voltage requirements will vary based on the specific year, make, and model of the vehicle.
Circuit Checks
The voltage requirements will vary based on the specific vehicle, the Brake Booster Pressure Sensor Circuit configuration, and the incorporated components. Refer to technical data to obtain the correct voltage range for the Brake Booster Pressure Sensor and follow the appropriate troubleshooting sequence. A sensor with no output voltage despite receiving the correct voltage input usually indicates internal failure.
If this process identifies the absence of a power source or ground, continuity testing may be necessary to check the condition of the wiring and connectors. Continuity tests should always be performed with the power removed from the circuit, and the normal readings should be 0 ohms of resistance unless otherwise specified by the technical data. Resistance or no continuity indicates faulty wiring or connectors that are shorted or open and must be repaired or replaced.
Common Repairs
We hope that the information in this article has been helpful in guiding you towards resolving the issue with your brake booster pressure sensor trouble code. This article is strictly informational, and the specific technical data and service bulletins for your vehicle should always take precedence.
