P0171 on a 2017 Jeep Compass

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 2017 Jeep Compass

Ranked from 228 NHTSA owner complaints filed for this vehicle.

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1
Faulty electronic throttle body / TPS
Medium severity
Multiple owners had the throttle body fail or get replaced, sometimes more than once, for power loss and ETC warnings; an inaccurate throttle position reading disrupts commanded airflow and fuel trim, contributing to a lean code.
Reported in 3 NHTSA complaints
Parts:throttle body
2
O2 sensor / fuel trim fault
Medium severity
One owner's check-engine light returned an O2-related code that persisted even after replacing spark plugs and the O2 sensor, suggesting an underlying lean condition rather than a simple sensor fault.
Reported in 1 NHTSA complaint
Parts:oxygen sensor
3
Vacuum or intake leak
Medium severity
The most common general cause of this code; unmetered air entering after the MAF sensor leans the mixture, especially noticeable at idle.
Common cause
4
Dirty or failing MAF sensor
Medium severity
Under-reports intake air volume so the PCM adds less fuel than the engine needs.
Common cause
Parts:mass air flow sensor
5
Weak fuel pump or clogged fuel filter
Medium severity
Reduced delivery pressure under load produces a lean condition that gets worse with RPM.
Common cause
Parts:fuel pump fuel filter
6
Stuck-open PCV valve
Low severity
Draws extra unmetered air into the intake, leaning the idle and light-load mixture.
Common cause
Parts:PCV valve
7
Intake manifold gasket leak
Medium severity
Lets outside air bypass the MAF directly into the intake, a classic lean-code source.
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