P0106 on Buick: How to Diagnose & Fix
MAP/Barometric Pressure Circuit Range/Performance
1 Buick model · 2 documented issues · $150-$900 repair
P0106 on Buick by model: symptoms, diagnosis and fix
This is the upstream half of the 1.4L PCV story and is often missed. The intake manifold on the LUV/LUJ 1.4T contains a small, non-serviceable orange one-way check valve in the PCV port. Under boost that valve is meant to block pressure from reaching the crankcase; when it fails and is ingested by the engine, boost pressure enters the crankcase, the camshaft-cover diaphragm tears, and the engine develops a large vacuum leak. The result is P1101 (intake airflow system performance) with P0171 (system too lean), rough idle, high idle, stalling and long-term fuel trims in the +25% to +70% range. Owners who replace only the valve cover watch the new one fail within months because the missing manifold check valve was never addressed. A ScannerDanner forum diagnosis of a 2019 Encore documents exactly this: check valve gone from the manifold, 70% fuel trim, fixed by an external PCV kit.
Common Symptoms
- Check engine light with P1101 and/or P0171
- Rough or surging idle
- High long-term fuel trims (+25% or more)
- Stalling at idle
- Whistle at the valve cover after diaphragm tears
- Repeat valve-cover failure after replacement
How to Fix
Pull the PCV hose at the intake manifold and look into the port: if the orange check valve is missing, the manifold is the root cause. Official repair is a new intake manifold (roughly $400-$700 installed) plus a new camshaft cover if the diaphragm has torn ($200-$350). Many owners instead install an external PCV fix kit (CruzeKits or equivalent) that relocates the check valve into a serviceable inline fitting, which is cheaper and prevents the repeat failure. Clear codes and confirm fuel trims return to single digits.
Sources for this issue (3)
The 1.4L turbocharged engine (LUV/LUJ family) used in the first-generation Encore is prone to a ruptured PCV pressure-regulator diaphragm built into the plastic camshaft (valve) cover. When the diaphragm cracks, unmetered air enters the intake, producing a loud high-pitched whistle or squeal that owners describe as a boiling tea kettle under the hood, along with rough idle and stalling at stops. GM acknowledged the defect with Special Coverage N202299080, extending warranty on the PCV/camshaft cover to 10 years / 120,000 miles for certain 2014 Encore (and related Cruze/Sonic/Trax) vehicles.
Common Symptoms
- Loud tea-kettle / boiling whistle under hood
- Check engine light
- Rough idle
- Stalling at idle or stoplights
- Vacuum leak
How to Fix
Replace the camshaft (valve) cover, which contains the integrated PCV diaphragm; many owners upgrade to a revised cover. The root-cause check valve in the intake manifold should also be addressed (replace manifold or install an external check-valve/PCV bypass kit) to prevent turbo boost from over-pressurizing the crankcase. Check eligibility under GM Special Coverage N202299080.
Sources for this issue (1)
P0106 code reference
General diagnostic-code context. The code alone does not confirm a cause for your vehicle; use the applicable issue card and its sources.
Frequently asked questions
What does P0106 mean on a Buick?
P0106 stands for "MAP/Barometric Pressure Circuit Range/Performance." P0106 means the manifold absolute pressure (MAP) or barometric pressure sensor signal is out of the expected range or not matching engine operating conditions (range/performance). The MAP sensor measures intake manifold pressure/vacuum, which the computer uses to gauge engine load and calculate the correct fuel and ignition timing. When the reading is implausible — too steady, not tracking throttle changes, or inconsistent with other sensors — the computer flags this code. Symptoms often include rough idle, hesitation, poor fuel economy, or a lack of power, and the cause may be the sensor, a vacuum leak, or wiring. On Buick it is documented across 1 model: Encore.
What are the most common causes of P0106?
The most common causes of P0106 are: Faulty MAP sensor, Vacuum leak or disconnected/cracked vacuum line to the sensor, Clogged or restricted MAP sensor port, Wiring or connector problems in the sensor circuit, Intake manifold leak affecting pressure readings, Restricted air intake or exhaust affecting manifold pressure, Poor ground or reference voltage to the sensor. The specific cause varies by vehicle.
How much does it cost to fix P0106 on a Buick?
Published repair estimates on Buick range from $150 to $900 depending on the model and root cause. If an issue mentions a recall or campaign, check your VIN with the manufacturer or NHTSA and confirm eligibility and coverage with a dealer.
Looking for P0106 on a different make?
View P0106 across all makes →Content compiled with AI assistance using NHTSA complaints, TSBs, and owner reports. May contain errors. Always verify with your vehicle's service manual.