P0171 on a 2020 Kia Telluride

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 2020 Kia Telluride

Ranked from 737 NHTSA owner complaints filed for this vehicle.

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1
Confirmed lean-running condition (companion codes logged on this vehicle)
Medium severity
One owner's scan directly captured companion codes P2177 and P2179 (bank lean at/off idle) alongside a fuel-rail-pressure code, which is direct on-vehicle confirmation of a lean-running condition consistent with P0171.
Reported in 1 NHTSA complaint
2
PCV valve malfunction
Medium severity
One report on this exact vehicle explicitly attributes oil loss/engine damage to a failing PCV valve; a PCV fault that admits excess unmetered crankcase air is a direct, documented cause of a lean-running condition.
Reported in 1 NHTSA complaint
Parts:pcv valve
3
Vacuum or intake air leak
Medium severity
Unmetered air entering after the MAF sensor (cracked intake boot, PCV hose, brake booster line) leans out the mixture; a smoke test or propane-around-the-intake test will find it.
Common cause
4
Dirty or failing MAF sensor
Medium severity
A contaminated or drifting MAF under-reports incoming air, so the PCM commands less fuel than the engine actually needs, producing a lean trim.
Common cause
Parts:mass air flow sensor
5
Weak fuel pump or clogged fuel filter
Medium severity
Insufficient fuel delivery/pressure under load can't keep pace with demand, showing up as lean trims that worsen at higher RPM or load.
Common cause
Parts:fuel pump fuel filter
6
Stuck-open PCV valve
Low severity
A PCV valve stuck open admits excess, unmetered crankcase air into the intake, leaning the mixture especially at idle.
Common cause
Parts:pcv valve
7
Exhaust leak upstream of the upstream O2 sensor
Low severity
A leak ahead of the front oxygen sensor draws in outside air that the sensor reads as excess oxygen, making the PCM think the mixture is lean when it isn't.
Common cause
8
Intake manifold gasket failure
Medium severity
A leaking manifold gasket lets in unmetered air, often worse at idle/vacuum and frequently paired with a rough or erratic idle.
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.

Rather have a pro handle it? Find a vetted local mechanic.

Matching symptoms

Car Runs Rough