P0556: Brake Booster Pressure Sensor Circuit Range/Performance
What Does P0556 Mean?
P0556 is a diagnostic trouble code indicating: Brake Booster Pressure Sensor Circuit Range/Performance. This code relates to the vehicle speed and idle control system. It has been reported in NHTSA complaints across 4 different vehicle models.
Symptoms of P0556
- ⚠️ Check engine light illuminated
- ⚠️ Vehicle won't start
Common Causes
- 🔍 Turbocharger or boost system issue
- 🔍 Sensor or control module malfunction
P0556 Reports by Year
Real Owner Reports
From NHTSA complaint database — actual owner descriptions.
"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 mult"
— Chevrolet Equinox owner, 02/04/2023
"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"
— Chevrolet Malibu owner, 05/08/2019
"As I was driving in a 45 MPH two-lane road, the car in front of me wanted to turn left and when I stepped on the brake pedal, it was stiff. The car wouldn't slow down. So, I quickly stepped on the parking brake which helped and possibly saved my life and the life/lives of those I could have hit. One"
— Chevrolet Malibu owner, 06/29/2022
Source: NHTSA Complaints Database
Most Reported Vehicles for P0556
Based on NHTSA owner complaint data.
| # | Vehicle | Reports |
|---|---|---|
| 1 | CHEVROLET MALIBU | |
| 2 | GMC TERRAIN | |
| 3 | CHEVROLET EQUINOX | |
| 4 | CHEVROLET TRAVERSE |
P0556 Reports by Vehicle
Detailed NHTSA complaint analysis for each vehicle model.
Frequently Asked Questions
Why does my car idle rough?
Can a dirty throttle body cause this?
What To Do Next
Possible Fixes
- 🔧 Have the code scanned with a professional-grade scanner to read freeze frame data
- 🔧 Test the relevant sensor(s) with a multimeter before replacing
- 🔧 If DIY repair isn't feasible, get a diagnostic from a trusted mechanic ($50-150)
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1
Find your vehicle above
Click your make and model for real owner reports and common causes specific to your vehicle.
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2
Check for recalls
Go to nhtsa.gov/recalls and enter your VIN. Free repairs if covered.
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3
Get a professional diagnosis
A code alone doesn't identify the exact failed part. A diagnostic ($50–$150) pinpoints the root cause.