P0171 on a 2024 Honda Cr V

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 2024 Honda Cr V

Ranked from 370 NHTSA owner complaints filed for this vehicle.

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1
Fuel injector failure (weak or clogged delivery)
High severity
The dominant pattern in this batch — dealers repeatedly condemned injectors (including all four on one car) after rough idle, RPM drop, and check-engine events consistent with a fuel-delivery shortfall.
Reported in 6 NHTSA complaints
Parts:fuel injector
2
Vacuum/intake air leak downstream of the MAF sensor
Medium severity
Unmetered air entering the intake — in this batch traced to EGR-related corrosion of the throttle body butterfly — leans the mixture and can set a lean-bank code.
Reported in 1 NHTSA complaint
Parts:throttle body
3
Weak fuel pump or restricted fuel filter
Medium severity
Reduced fuel delivery pressure under load is a common contributor to a lean-bank code.
Common cause
Parts:fuel pump fuel filter
4
Dirty or failing mass airflow (MAF) sensor
Medium severity
A MAF sensor that under-reports incoming air causes the ECM to add too little fuel, producing a lean condition.
Common cause
Parts:MAF sensor
5
Stuck-open PCV valve
Low severity
A PCV valve stuck open draws unmetered air into the intake, particularly noticeable at idle, and is a common lean-code cause.
Common cause
Parts:PCV valve
6
Exhaust leak upstream of the front O2/air-fuel sensor
Low severity
Outside air drawn in through a manifold or header leak skews the upstream sensor reading lean.
Common cause
7
Intake manifold gasket leak
Medium severity
A leaking manifold gasket is a classic unmetered-air source that produces a persistent lean-bank code.
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