P0171 on a 2016 Chevrolet Traverse

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 2016 Chevrolet Traverse

Ranked from 290 NHTSA owner complaints filed for this vehicle.

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1
Weak fuel pump or clogged fuel filter
Medium severity
Two complaints describe the engine shutting off at idle/stops and dragging on acceleration, consistent with insufficient fuel delivery causing a lean condition.
Reported in 2 NHTSA complaints
Parts:fuel pump fuel filter
2
Running-lean fuel trim with O2 sensor fault
Medium severity
An independent shop diagnostic on this vehicle documented multiple codes for running lean together with an O2 sensor fault, directly matching this code's failure mode.
Reported in 1 NHTSA complaint
Parts:oxygen sensor
3
Fuel vapor lock / restricted fuel delivery in hot weather
Medium severity
One owner reported stalling and lack of performance in hot weather traced to vapor buildup in the fuel line, which can starve fuel delivery and lean the mixture.
Reported in 1 NHTSA complaint
4
Vacuum or intake air leak
Medium severity
A cracked intake boot, PCV hose, or brake booster line lets in unmetered air; smoke-test the intake tract.
Common cause
5
Dirty or failing mass airflow (MAF) sensor
Medium severity
A fouled or drifting MAF underreports airflow, causing the ECU to under-fuel; compare live MAF data to spec.
Common cause
Parts:mass airflow sensor
6
Stuck-open PCV valve
Low severity
Excess air pulled through a failed PCV valve leans the mixture at idle; check for a valve that doesn't rattle/seat properly.
Common cause
Parts:PCV valve
7
Intake manifold gasket leak
Medium severity
A failed intake gasket is a common unmetered-air path on this platform; look for a lean condition that's worse at 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