P0556
8 owner reports and 384 manufacturer filings across 38 model years from Chevrolet, Dodge, GMC, Jeep and others.
Where P0556 shows up
Source: NHTSA manufacturer communications and complaintsA model year appears here because the code is named in its record, not because every one of these vehicles sets it. Counts are mentions in the federal files, not failure rates — nobody publishes the denominator.
What it gets filed under
What owners said
Source: NHTSA complaint databaseOwners’ own words, one per nameplate, scrubbed of anything identifying. These are unverified reports filed with NHTSA — they are what was said, not a finding that it was true.
A scan of the vehicle's OBD-II codes revealed codes P0556 (Brake Booster Pressure Sensor Circuit), P0014 (Exhaust Camshaft Position Timing Over-Advanced), and P0017 (Crankshaft Position - Camshaft Position Correlation)
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
P0014, P0017, and P0556 codes were pulled before having it towed to the first mechanic
The dealer performed diagnostics and made two repairs based on generated codes (C1223-68 & P0556)
Manufacturer filings that name it
Source: NHTSA manufacturer communicationsService bulletins and campaigns whose filed summary names P0556. Quoting the document number at a service desk is often the fastest route to a diagnosis someone has already written down.
- 18-104-222022-05-26 · Power Train
- Flash: Powertrain Control Module (PCM) Updates This bulletin involves reprogramming the PCM with the latest available software. Customers may experience a Malfunction Indicator Lamp (MIL) illumination. Upon further investigation the technician may find that one or more of the following DTCs have been set: P0556 - Brake Booster Pressure Sensor Circuit Performance. P0340 - Cam Position Sensor Circ
- 18-103-222022-05-25 · Electrical System
- Flash: Powertrain Control Module (PCM) Updates This bulletin involves reprogramming the PCM with the latest available software. Customers may experience a Malfunction Indicator Lamp (MIL) illumination. Upon further investigation the technician may find the following Diagnostic Trouble Code (DTC) has been set:P0556 - Brake Booster Pressure Sensor Circuit Performance. Customer may describe the fo
- 18-098-222022-05-19 · Power Train — Manual Transmission — Control Module (Tcm/Pcm/Tecm)
- Flash: Powertrain Control Module (PCM) Updates This bulletin involves reprogramming the PCM with the latest available software. Customers may experience a Malfunction Indicator Lamp (MIL) illumination. Upon further investigation the technician may find the following Diagnostic Trouble Code (DTC) have been set: P0556 - Brake Booster Pressure Sensor Circuit Performance. Customer may describe the f
- 18-095-222022-05-17 · Electrical System
- Flash: Powertrain Control Module (PCM) Updates This bulletin involves reprogramming the PCM with the latest available software. Customers may experience a Malfunction Indicator Lamp (MIL) illumination. Upon further investigation the technician may find the following Diagnostic Trouble Code (DTC) has been set: P0556 - Brake Booster Pressure Sensor Circuit Performance.
- VIN4APIN202101142021-01-14 · Electrical System
- Customer states MIL-on with P0556 Customer states MIL-on with P2421 Customer states MIL-on with Misfire code Customer states clutch pedal makes noise No crank, no start Customer states no voice output during calls / micro phone inoperative Customer states fuel odor/leak in the rear part of the vehicle (without a punctured fuel tank, hoses or pipes) or difficulty fueling fuel tank or fuel com
- VIN4APIN202101042021-01-04 · Equipment
- Customer states MIL-on with P0556 Customer states MIL-on with P2421 Customer states MIL-on with Misfire code Customer states clutch pedal makes noise No crank, no start Customer states no voice output during calls / micro phone inoperative Customer states fuel odor/leak in the rear part of the vehicle (without a punctured fuel tank, hoses or pipes) or difficulty fueling fuel tank or fuel com
What P0556 means
Source: SAE J2012 / OBD-IIP0556 sits in the generic range of the OBD-II standard, so it means the same thing on every vehicle sold in the United States — but WhichTrim does not carry a definition for it and will not invent one. What is on this page is the record: who named it and on what.
A stored code names the test that failed, never the part that caused it. It is the starting point of a diagnosis, not its conclusion — the same code has several possible causes and the cheap one is not always right.
Common questions about P0556
Source: NHTSA files and the OBD-II standardCan I keep driving with P0556 stored?
Nobody can answer that from the code alone, and a site that does is guessing. A steady light generally means the fault was logged and the vehicle is in a reduced-risk mode; a flashing light means stop soon, because a misfiring engine can destroy a catalytic converter in minutes. The safe read of this page is the mileage and the components, not permission.
Does a code mean the car is recalled?
No. Recalls are filed by campaign and matched by VIN, and none of them are triggered by a scan tool. If you want to know whether an open recall applies to one specific vehicle, check the VIN at nhtsa.gov/recalls — that is the only source that settles it.
Why do the counts here differ from other sites?
Because these are not estimates. Every number on this page is a count of documents in NHTSA's own files: manufacturer communications that name the code in their filed summary, and owner complaints that name it in the narrative. We do not model, weight or extrapolate them.
Will clearing the code fix it?
Clearing turns the light off and erases the freeze-frame data a technician would have used to work out what happened. If the condition is still there the code returns, usually within a few drive cycles, and the diagnosis now starts from less information than before.