Error Code P0556 is defined as Brake Booster Pressure Sensor Circuit Range/Performance. This means a problem in the brake booster pressure sensor circuit has been determined, which could be caused by shorted electrical circuitry or faulty valves.
This code is a generic trouble code, meaning it applies to all cars equipped with the OBD-system and brake booster pressure sensor. It’s particularly common, but not limited to Acura, Alfa Romeo, Chevrolet, Dodge, Ford, Hyundai, Nissan, Pontiac, Subaru, etc. Though generic, specifications on the definition, troubleshooting, and repairs may vary from year, make, model, and powertrain configurations of your 2010 Mazda B Series .
The job of the brake booster pressure sensor circuit is to monitor the amount of pressure (vacuum) applied to the power brake booster. This process is controlled by the PCM to allow your 2010 Mazda B Series to adapt to various braking situations and adjust the pressure needed by your 2010 Mazda B Series to assist the operation of the brake pedal. This process is crucial for the power brakes to work efficiently and safely, and safely slow down or stop your 2010 Mazda B Series with a minimum amount of foot pressure being applied to your 2010 Mazda B Series .
Error Code P0556 is one of the many possible codes associated with the brake booster pressure sensor circuit. When this appears, it means the PCM (powertrain control module, also known as ECM or engine control module in other 2010 Mazda B Series makes) has determined an error indicating that the brake booster pressure sensor circuit is out of range, or not running properly due to abnormal feedback.
Specific situations determine the code which the PCM activates. Other related brake booster pressure sensor circuit error codes include:
For some cars, this code only appears when applying the brakes. While for other makes, a 2010 Mazda B Series may require multiple ignition cycles before this code pops up.
When this code appears, it will illuminate the Check Engine light, or flash it when braking. Other common symptoms include:
As with most trouble codes, it is best to refer with your TSB (Technical Service Bulletin) when troubleshooting this code.
Start by locating all components related to the Brake Booster Pressure Sensor Circuit. This includes the sensor itself, the brake booster, vacuum lines, wirings, and connectors to the PCM. As soon as you find these components, inspect the connectors and wirings for signs of damages, such as scraping, bare wires, burn spots, rubbing, etc. Also, check the connectors for signs of corrosions buildup, or damaged pins. Vacuum lines must be checked for weather cracks, leaks, and overall serviceability level.
Next step for diagnosis is usually 2010 Mazda B Series specific and may require the appropriate and advanced equipment to be conducted properly. This includes the use of a digital multimeter, and specific technical references for your 2010 Mazda B Series , as the voltage requirement is usually based on the make, model, and specific year of your 2010 Mazda B Series .
As said earlier, the voltage requirement will vary from 2010 Mazda B Series to 2010 Mazda B Series , the configuration of the brake booster pressure sensor circuit, and all components incorporated into the system. Thus, tech data must be referenced to obtain the right voltage range from the brake booster pressure sensor and the appropriate troubleshooting sequence.
The correct voltage input to a sensor without output voltage is usually a sign of internal failure.
If this process confirms the absence of a power source or ground, then you should conduct a continuity test to check the condition of the connectors and wirings. This test is always performed with power removed from the circuit, while normal readings should start at 0 ohms of resistance unless otherwise specified by the technical data from the TSB.
Resistance or no continuity means there’s a faulty wiring or connector issue that is shorted or open, which must be repaired, if not replaced.