P0171 on a 2018 Jeep Grand Cherokee Srt

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 2018 Jeep Grand Cherokee Srt

Ranked from 685 NHTSA owner complaints filed for this vehicle.

Sort by:

1
Weak or failing fuel pump
High severity
Owners reported slow-crank/hard-start symptoms tied to known high-pressure fuel pump issues on this engine, and a weak pump can't maintain the pressure needed to keep the mixture from leaning out.
Reported in 2 NHTSA complaints
Parts:fuel pump
2
Carbon-fouled intake manifold / EGR passages
Medium severity
One vehicle had the intake manifold fail alongside the EGR valve with heavy carbon deposits, which can disrupt intended airflow and create a lean condition.
Reported in 1 NHTSA complaint
Parts:intake manifold gasket
3
Vacuum or intake leak
High severity
Unmetered air entering downstream of the MAF sensor is the single most common cause of a system-too-lean code.
Common cause
4
Dirty or failing mass air flow (MAF) sensor
Medium severity
A contaminated or drifting MAF under-reports incoming air, causing the PCM to under-fuel the engine.
Common cause
Parts:mass airflow sensor
5
Stuck-open PCV valve
Medium severity
A PCV valve stuck open acts like an uncontrolled vacuum leak, especially noticeable at idle.
Common cause
Parts:PCV valve
6
Exhaust leak upstream of the front O2 sensor
Low severity
Outside air pulled in through a leak ahead of the sensor makes the PCM think the mixture is leaner than it actually is.
Common cause
7
Clogged fuel filter
Medium severity
Restricted fuel flow to the rail can drop fuel pressure enough to lean out the mixture under load.
Common cause
Parts:fuel filter

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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