Fault Code Lookup › Powertrain codes › P0556
P0556 Powertrain · generic OBD-II
Brake Booster Pressure Sensor Circuit Range/Performance
P0556 is a standard code covering engine, transmission, fuel and emissions. It names the system that logged the fault, not the part that failed. Below: which cars owners reported it on, what happened, and recalls on those cars, from 15 complaints filed with NHTSA. Updated November 9, 2026.
- 15owner reports
- 9car models
- 0mention a crash
- 0mention a fire
- 2016–2023model years
Which cars get code P0556?
Every model whose owners mentioned P0556 in a complaint, most reports first. Each year opens that car's full problem report. Popular models collect more reports because more of them are on the road.
GMC Terrain
5 reportsChevrolet Equinox
1 reportChevrolet Impala
1 reportChevrolet Impala Limited
1 reportChevrolet Malibu Limited
1 reportChevrolet Traverse
1 reportFord F-150
1 reportRam ProMaster
1 reportWhere does P0556 show up?
By brand
- Chevrolet8
- GMC5
- Ford1
- Ram1
Component the owner filed it under
Is there a recall for P0556?
The others concern the component owners file this code under (Service Brakes) on the same cars; they may or may not relate to the code. Recall repairs are free; check your VIN at nhtsa.gov/recalls.
Service Brakes, Hydraulic: Foundation Components: Master Cylinder Ford Motor Company (Ford) is recalling certain 2017-2018 F-150, Expedition, and Lincoln Navigator vehicles. The brake master cylinder may allow brake fluid to leak from the front wheel circuit into the brake booster.
2017 Ford F-150. Full risk and remedy on each car's report.
Service Brakes, Hydraulic: Power Assist Ford Motor Company (Ford) is recalling certain 2016-2017 Ford Expedition, Lincoln Navigator, and 2016-2018 F-150 vehicles equipped with 3.5L Ecoboost engines. The brake master cylinder may allow brake fluid to leak from the front wheel circuit into the brake booster.
2017 Ford F-150. Full risk and remedy on each car's report.
Service Brakes, Hydraulic: Foundation Components: Master Cylinder Ford Motor Company (Ford) is recalling certain 2014-2017 F-150 pickup trucks equipped with 3.5L Ecoboost engines. The brake master cylinder may leak brake fluid into the brake booster.
2017 Ford F-150. Full risk and remedy on each car's report.
Service Brakes, Hydraulic: Foundation Components: Disc: Caliper General Motors LLC (GM) is recalling certain 2020 Chevrolet Equinox vehicles. The rear brake calipers may have been produced with an incorrect lubricant, potentially causing the rubber seals to swell and the brakes to drag.
2020 Chevrolet Equinox. Full risk and remedy on each car's report.
Service Brakes, Hydraulic: Foundation Components: Disc: Caliper General Motors LLC (GM) is recalling certain 2018-2019 Chevrolet Equinox, Impala, Cruze, Volt and Bolt EV vehicles, GMC Terrain vehicles, Buick Lacrosse and Regal vehicles, Cadillac XTS and XTS Professional vehicles and 2018 Chevrolet Malibu vehicles. The rear brake caliper pistons may have an…
2018 GMC Terrain. Full risk and remedy on each car's report.
What happened when owners saw P0556?
10 of the 15 reports, spread across the models above, as the owners wrote them. NHTSA removes names and VINs; long reports are trimmed. CarHooq has not verified individual claims.
Vehicle was being driven at 60 mph on the highway when the brakes weren't responding as I was entering a sharp curve. Had to stand on the brakes and manually lower the gears to keep from hitting a tree head-on. Check engine light was on. P0014, P0017, and P0556 codes were pulled before having it towed to the first mechanic. Car wouldn't start after it was parked after the initial incident. The first mechanic was unable to diagnose so the vehicle was towed to the Chevrolet Dealership. They say the brake vacuum pump malfunctioned and caused permanent damage to the engine rendering the car inoperable and I will have to have a new engine installed. The car drove fine prior to the vacuum pump…
…Diagnostic trouble codes included P0014, P0017, and P0556. The dealership estimated repairs at $5,960.79 but advised that the proposed repairs might not remove all internal metal debris. The service advisor stated that replacing the engine would be the only way to guarantee complete debris removal. GM has published technical service information, including PIP5835 and Bulletin 21-NA-268, addressing similar vacuum pump failures and associated damage. The vehicle remains unrepaired. I am reporting this incident because an unexpected loss of power brake assist at highway speeds, without advance warning, creates a significant collision risk for drivers, passengers, and other motorists…
The P0556 code gets stored when the PCM has detected a problem with the brake booster pressure sensor circuit because of abnormal feedback. Braking distance significantly affected by brake pedal becoming difficult to depress. Cause is the brake booster vacuum pump. Internet reports indicate multiple vehicle types during the late 20-teens and early 2020s. Problems are occurring during or shortly after warranty expiration. This is a very dangerous problem that could cause serious injury.
TL* THE CONTACT OWNS A 2016 CHEVROLET MALIBU. WHILE DRIVING AND DEPRESSING THE BRAKE PEDAL, THE PEDAL TRAVELED TO THE FLOORBOARD AND THERE WAS A GRINDING NOISE. THERE WAS NO WARNING INDICATOR ILLUMINATED. IN ADDITION, THE VEHICLE LOST POWER AND FAILED TO ACCELERATE. KELLER CHEVROLET (LOCATED AT 3600 GENESEE ST, CHEEKTOWAGA, NY 14225, (716) 650-4589) STATED THAT THE VIN WAS NOT INCLUDED IN A RECALL. THE CONTACT PERFORMED HIS OWN DIAGNOSTIC TESTING AND RETRIEVED FAILURE CODE: P0556 (BRAKE BOOSTER PRESSURE). THE DEALER AND MANUFACTURER WERE NOT NOTIFIED OF THE FAILURE. THE APPROXIMATE FAILURE MILEAGE WAS 32,000.
While practicing parallel parking in the vehicle for about 1 hour, upon leaving the parking lot, there was a message that popped up on the dashboard reading, “SERVICE BRAKE ASSIST”. When driving the vehicle out the parking lot, the brakes were hard when pressing and the vehicle took a while to brake. I found myself braking at a far distance in order to stop the car at the nearest stop light. I turned my emergency lights and drove carefully home, since the engine light came on, which I parked and turned off the car. The next day, I turn on the vehicle and the engine light is still on, I take it to the local Auto Zone for a code, code P0556 is showing BRAKE BOOSTER PRESSURE SENSOR. I then call…
Brake Booster failed to operate. When driving and needing to stop the brake peddle was stiff and would not compress failing to safely stop the vehicle. I had to stand on the brakes as hard as I could to come to a stop. Shortly afterwards the dashboard alerted me to Check Brake System. Upon reading DTCs it showed P0555 (Brake Booster Pressure Sensor Circuit) and P0556 (Brake Booster Pressure Sensor Circuit Range/Performance). Vehicle no longer is safe to operate. I had this issue back in 2019 on several occasions but it was intermittent and self resolved itself after pumping the brakes. I took it to a Ford dealership. They kept the truck for 2 months saying they couldn’t duplicate the issue…
On August 5, I descended on California Highway 88 East from the Carson Pass; less than 1 mile down a warning appeared to “Service Brake System”. The warning disappeared but the “brake” light on the instrument cluster remained on. I took the vehicle to Carson Dodge on August 6. The dealer performed diagnostics and made two repairs based on generated codes (C1223-68 & P0556). I picked it up on August 13 and drove about 200 miles; the warning re-appeared each time I drove it. I returned the vehicle to Carson Dodge on August 16. The “brake” warning was visible both times it was in for service. The 8/16 work order shows the same problem codes as the August 6 work order. The 8/16 order states that…
…The mechanic retrieved DTC: P0556 (Brake Booster Pressure Sensor) failure. The mechanic also determined that the brake vacuum booster pump needed to be replaced. The vehicle had not been repaired. The manufacturer had not been informed of the failure. The failure mileage was 84,697.
…A diagnostic scan performed after the incident showed code P0556 for the brake booster pressure sensor circuit range/performance. The GMC dealership later diagnosed problems involving the vacuum pump, exhaust camshaft, and timing components and recommended replacement of the vacuum pump, exhaust camshaft, timing components, and related parts.” The sudden loss of braking assistance created a serious safety hazard and could have resulted in a collision, serious injury, or death. The vehicle is currently available for inspection.
I purchased a 2019 chevy malibu on April 9th 2022. Car seemed to be fine at first drove car for two month experienced frequent shift to park issues as car would not recognize itself in park Until multiple attempts at parking. I was arrested on June 4th 2022 and came home on September 5th and attempted to start my car. Car cranked multiple times before starting stalling and cutting itself off while display engine power reduced and check engine light. I used Obd computer and car codes p0014 p0017 p0556. Vehicle was taken to Hertrich Chevy of Salisbury Maryland. The technician informed me that I needed a engine replaced due to nature of damage upon diagnostic chevy discovered vehicle had little…
P0556: questions drivers ask
What does code P0556 mean?
P0556 is a generic OBD-II powertrain code. Its standard definition is "Brake Booster Pressure Sensor Circuit Range/Performance". The code tells you which system set the fault, not which part failed; the owner reports on this page show what it meant in practice for 9 car models.
Which cars get code P0556 most often?
In NHTSA owner complaints, P0556 is mentioned most for the Chevrolet Malibu (6), GMC Terrain (5), Chevrolet Equinox (1), across 9 models and model years 2016 to 2023. Popular models collect more reports because more of them are on the road.
Is there a recall for code P0556?
No NHTSA recall text names P0556 directly. 5 recalls on the cars that report this code concern the same component owners name most (Service Brakes); they may or may not relate to the code. Check your VIN at nhtsa.gov/recalls.
What should I do if my car shows P0556?
Write down when the code appeared and what the car did (warning lights, loss of power, noises, speed, weather). Check your VIN for open recalls at nhtsa.gov/recalls, ask a dealer or independent workshop to read the stored freeze-frame data before anyone clears the code, and keep the repair order. If the car loses power in traffic, stop driving it. CarHooq does not diagnose: these are owner reports and official recall notices, not repair advice.
How this page was made
CarHooq read the text of every owner complaint filed with NHTSA for 19 US and European brands (model years 2012 onwards) and picked out the diagnostic trouble codes owners wrote down. This page lists every mention of P0556. The definition is the generic SAE J2012 wording; a carmaker may use the code slightly differently. Nothing here is a diagnosis. More answers: the fault code FAQ. Data: NHTSA Office of Defects Investigation (public domain), retrieved November 9, 2026. How CarHooq reports are made.
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