P0557 OBD-II Trouble Code: Brake Booster Pressure Sensor Circuit Low

Our certified mechanics come to you · Get a fair and transparent estimate upfront

Red-stars EXCELLENT RATING ON

Cost of diagnosing the P0557 code

P0557 is a diagnostic trouble code (DTC) for "Brake Booster Pressure Sensor Circuit Low". This can happen for multiple reasons and a mechanic needs to diagnose the specific cause for this code to be triggered in your situation. Our certified mobile mechanics can come to your home or office to perform the Check Engine Light diagnostic. Once we are able to diagnose the problem, you will be provided with an upfront quote for the recommended fix and receive $20.00 off as a credit towards the repair. All our repairs are backed by our 12-month / 12,000-mile warranty.

Cars Estimate Credit towards follow-up repair Earliest Availability
Ford$20.00
Toyota$20.00
BMW$20.00
SCHEDULE P0557 DIAGNOSTIC Get a fair and transparent estimate upfront

P0557 code definition

The P0577 vehicle trouble code indicates an issue with the brake booster pressure sensor circuit.

What the P0557 code means

The P0577 code identifies a pressure problem within the brake booster. When the brake booster pressure sensor fails to send a voltage input signal to the PCM that is satisfactory (or proportionate to the vehicle velocity required) the P0557 code will be stored. This usually indicates that the brakes were applied and the pressure within the brake system was not sufficiently to factory specifications.

Some vehicles will require multiple ignition cycles in which this problem occurs to trigger the check engine indicator light, but the P0557 code will still be stored, sometimes as a “pending code” if the issue is only an initial failure.

What causes the P0557 code?

The P0557 code has a number of common causes:

  • An issue with the brake booster pressure sensor
  • Vacuum leaks into the vacuum brake booster
  • Defective or broken vacuum hoses
  • Defective or broken electrical circuitry

If your vehicle’s brake boosters are hydraulic:

What are the symptoms of the P0557 code?

When the P0557 code appears, it is usually accompanied by the Check Engine light illuminating on the vehicle’s dashboard. Depending on the source of the problem, physical symptoms of a brake issue may be present before the Check Engine light illuminates. The brake pedal may be unresponsive or softer than usual. Brake performance may be affected. In some cases, brake performance is not affected but the feel of the brake pedal is still noticeably softer. It may take multiple presses of the brake pedal to cause the OBD-II system to store the P0557 code.

How does a mechanic diagnose the P0557 code?

A qualified technician with an OBD-II code scanner capable of retrieving factory readings from the vehicle. The technician will view the trouble code and see the time that it was stored. After that has been observed, the codes will be cleared before the vehicle is taken for a test drive. If, during the course of the drive, the code appears again, then it will be confirmed that the problem is indeed related to the P0557 code and not an intermittent issue that may be caused by electrical malfunctions.

Once the P0557 code is confirmed as the source of the problem, then the diagnosis can move onto the next step. The technician will use a voltmeter to test the circuits around the brake booster pressure sensor and the powertrain control module. A visual inspection of the wires and connections will then take place. After that, the inspection will move onto the brake booster itself and all of the vacuum lines surrounding it.

Common mistakes when diagnosing the P0557 code

While a malfunctioning brake booster will cause the P0557 code to appear, the code can also be caused by an electrical malfunction or a leaking vacuum line. In applications that use a hydraulic brake booster, leaking hydraulic fluid lines and leaky connections can cause the P0557 code to appear. The sensor responsible for monitoring pressure within the brake booster is prone to malfunctioning as well. If this sensor cannot properly read and relay that data, the P0557 code will appear.

How serious is the P0557 code?

The P0557 code is serious enough to warrant getting a professional to diagnose the problem as soon as the code appears. A problem with the brakes is inherently hazardous, and declining brake performance is dangerously unpredictable. The code itself will not prevent the engine from starting, but that does not mean that the vehicle is safe to drive when the brake booster does not have proper pressure.

What repairs can fix the P0557 code?

The most common repairs to address the P0557 code are as follows:

Additional comments for consideration regarding the P0557 code

Do not replace parts such as the brake booster prior to having the P0557 code diagnosed by a qualified technician. Often the problem is rooted in an electrical malfunction or a leaking vacuum line within the brake system.

Need help with a P0557 code?

YourMechanic offers certified mobile mechanics who will come to your home or office to diagnose and repair your vehicle. Get a quote and book an appointment online or speak to a service advisor at 1-800-701-6230.

P0557
trouble codes
OBD-II

No more waiting rooms! Our mechanics will come to you to diagnose and fix the P0557 code.

SCHEDULE P0557 DIAGNOSTIC
Get a $20 credit for the follow-up repair

Recent Check Engine Light is on Inspection reviews

Excellent Rating


YourMechanic Check Engine Light is on Inspection Service

Average Rating

4.8/5

Number of Reviews

5,156

Rating Summary
4,752
196
50
27
131
4,752
196
50
27
131

Al

21 years of experience
14 reviews
Al
21 years of experience
Nissan Pathfinder - Check Engine Light is on - Atlanta, Georgia
Al, was cool and very knowledgeable. Being direct and upfront always works. Al, is a credit to the company.

Xavier

10 years of experience
20 reviews
Xavier
10 years of experience
Chevrolet Equinox - Check Engine Light is on - Frisco, Texas
Xavier was GREAT!!! He made sure that I understood everything that he did to my vehicle and answered all my questions. Very thorough and even worked thru the light rain that we had. When I have to use this service again, I hope to be able to request him!

Luis

14 years of experience
52 reviews
Luis
14 years of experience
Kia Sorento - Check Engine Light is on - Las Vegas, Nevada
Luis did an excellent job in determining that this was a warranty issue on bad parts. He has integrity and is good at what he does. I would highly recommend him for any auto repairs that come up.

Reginald

36 years of experience
32 reviews
Reginald
36 years of experience
BMW 325i - Check Engine Light is on - Los Angeles, California
Reginald was incredibly helpful in helping me to diagnose several issues in my car, as well as repair issues to help me pass a break and light test. He even went so far as to come to the brake and light testing location so that he could ensure that the car passed and be there if anything else needed to be fixed on the spot. Absolutely would recommend him to anyone who is looking for an honest and knowledgeable mechanic!


More related articles

P0645 OBD-II Trouble Code: A/C Clutch Relay Control Circuit
P0645 means there is an issue within the A/C clutch relay control circuit often due too a defective A/C compressor driver or control relay.
B1843 OBD-II Trouble Code: Wiper Front Power Circuit Short to Ground
B1843 means there is an error with the wiper front power circuit, likely due to a faulty electrical component.
P1103 OBD-II Trouble Code: Mass Airflow Sensor in Range But Higher Than Expected
P1103 means there is an issue with the mass airflow sensor, likely due to faulty or loose wiring and connectors in the sensor, or an air leak.

Related questions

Problem starting after fueling have to give it to start

Hello. All modern cars are equipped with an Evaporative Emission Control (EVAP) system. The EVAP system prevents fuel vapors from the fuel tank from escaping into the atmosphere. The EVAP system collects and temporarily stores the fuel vapors in the...

Why is my car sputtering? 2005 Saturn Ion

Hi there - a car that sputters may have an ignition misfire, or a fuel supply issue causing this behavior. You mentioned the Check Engine Light is on - getting the problem codes is task #1. The problem codes will...

Stalls when turning or at a stop

Hi there. The first step is to check for any problem codes stored by engine management. This can save a lot of time money when diagnosing drive-ability problems. Most auto parts stores will do this for free. Several problems could...

How can we help?

Our service team is available 7 days a week, Monday - Friday from 6 AM to 5 PM PST, Saturday - Sunday 7 AM - 4 PM PST.

1 (855) 347-2779 · hi@yourmechanic.com