P0171 on a 2022 Hyundai Tucson

P0171 means the engine computer is adding more fuel than normal on bank 1 because it sees too much air or not enough fuel.

Not your vehicle? See general P0171 info.

Most common causes on the 2022 Hyundai Tucson

Ranked from 364 NHTSA owner complaints filed for this vehicle.

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1
Leaking/misfiring GDI fuel injector(s) causing a false lean reading (TSB 22-FL-002H / 23-FL-002H-1)
High severity
The dominant theme in these complaints is repeated high-pressure fuel injector failure; a misfiring cylinder passes unburned oxygen past the oxygen sensors, which the PCM reads as a lean condition even though the injector itself may be over- or under-fueling.
Reported in 20 NHTSA complaints
Parts:fuel injector
2
EGR valve failure
Medium severity
One owner had two separate EGR valve failures, which can affect the air/fuel charge and trims read by the PCM.
Reported in 1 NHTSA complaint
Parts:EGR valve
3
Vacuum or intake leak
Medium severity
Unmetered air entering downstream of the MAF sensor is a classic, straightforward cause of a lean code.
Common cause
Parts:intake manifold gasket vacuum hose
4
Dirty or failing MAF sensor
Medium severity
A contaminated or drifting MAF under-reports intake air, causing under-fueling.
Common cause
Parts:mass air flow sensor
5
Weak fuel pump or clogged fuel filter
Medium severity
Reduced fuel delivery under load leans the mixture, especially at higher RPM/load.
Common cause
Parts:fuel pump fuel filter
6
Stuck-open PCV valve
Medium severity
A PCV valve stuck open draws excess unmetered air into the intake.
Common cause
Parts:PCV valve
7
Intake manifold gasket failure
Medium severity
A leaking intake gasket admits unmetered air right at the manifold, leaning the mixture.
Common cause
Parts:intake manifold gasket

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These causes are aggregated from NHTSA owner complaints and general repair knowledge — this is not a diagnosis. P0171 on your car still needs shop confirmation before any repair.

Common symptoms

Check engine light
Rough idle
Hesitation
Surging idle
Poor fuel economy

What to check before replacing parts

Review short- and long-term fuel trims on bank 1

Look for: High positive trims (commonly worse at idle, improving with RPM) mean the computer is adding fuel to compensate for excess air or insufficient fuel — that pattern is this code's fingerprint.

Smoke-test the intake

Look for: Smoke escaping (or a hiss you can hear) at intake boots, gaskets, or vacuum hose connections confirms unmetered air is entering after the MAF sensor, which is the most common cause of a lean code.

Inspect the PCV hoses and valve

Look for: A cracked, split, or disconnected PCV hose, or a PCV valve stuck open, draws in extra unmetered air the same way a vacuum leak does.

Clean and test the MAF sensor

Look for: Visible dirt or oil film on the sensor element, or a grams/second reading that doesn't track expected airflow for RPM, means the MAF is under-reporting air and causing the computer to under-fuel.

Verify fuel pressure

Look for: Pressure below spec (weak pump, clogged filter, failing regulator) starves the engine of fuel and produces the same lean trim pattern as a vacuum leak — rule it out before chasing leaks.

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Matching symptoms

Car Runs Rough