P0171 on a 2013 Chevrolet Equinox

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 2013 Chevrolet Equinox

Ranked from 747 NHTSA owner complaints filed for this vehicle.

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1
Excessive Oil Consumption / Piston Ring Wear
High severity
Worn piston rings cause excessive oil consumption, leading to low oil levels, internal engine damage, and potential vacuum/timing issues that trigger lean codes.
Reported in 16 NHTSA complaints
2
Frozen PCV Valve / Blown Rear Main Seal
High severity
The PCV valve freezes in cold weather due to moisture buildup, causing crankcase pressure to blow out the rear main seal, leading to massive vacuum leaks and oil loss.
Reported in 4 NHTSA complaints
3
Timing Chain Failure / VVT Component Failure
High severity
Oil starvation from excessive consumption leads to timing chain tension loss, stretching, or failure, as well as VVT solenoid failure, causing poor running conditions and lean codes.
Reported in 4 NHTSA complaints
4
Exhaust Manifold Leak
Medium severity
A cracked exhaust manifold or leaking gasket introduces unmetered oxygen into the exhaust stream before the O2 sensor, falsely indicating a lean condition.
Reported in 1 NHTSA complaint
5
Vacuum Leaks (Intake Manifold, Hoses)
Medium severity
Unmetered air entering the intake manifold past the MAF sensor causes a lean condition. Look for cracked hoses or failed intake gaskets.
Common cause
6
Faulty Mass Air Flow (MAF) Sensor
Medium severity
A dirty or failing MAF sensor under-reports the amount of air entering the engine, causing the ECM to provide insufficient fuel.
Common cause
7
Low Fuel Pressure (Failing Fuel Pump or Clogged Filter)
Medium severity
Insufficient fuel delivery to the injectors prevents the engine from maintaining the proper air/fuel ratio, resulting in a lean condition.
Common cause
8
Clogged or Faulty Fuel Injectors
Medium severity
Restricted fuel injectors fail to spray the commanded amount of fuel into the cylinders, causing a lean mixture.
Common cause
9
Faulty Upstream Oxygen (O2) Sensor
Low severity
A degraded or failing O2 sensor can falsely report a lean condition to the ECM, triggering the code.
Common cause

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