P0171 on a 2015 Honda Accord Hybrid

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 2015 Honda Accord Hybrid

Ranked from 609 NHTSA owner complaints filed for this vehicle.

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1
Weak or failing fuel pump (fuel-delivery pressure loss)
High severity
A large cluster of owners report sudden loss of power/stall, several explicitly tied to the 2013-2017 Accord fuel pump recall or shop-confirmed fuel pump failure; insufficient fuel pressure reads lean under load.
Reported in 6 NHTSA complaints
Parts:fuel pump
2
Vacuum/intake air leak from a deteriorated intake manifold gasket or plenum
Medium severity
An owner's intake manifold plenum corroded and broke down, causing unmetered air to enter and lean out bank 1 — the plenum's known failure mode on this generation of engine.
Reported in 1 NHTSA complaint
Parts:intake manifold gasket
3
Dirty or failing MAF sensor
Medium severity
A contaminated or drifting mass airflow sensor under-reports incoming air, causing the PCM to command less fuel than needed and trip a lean code.
Common cause
Parts:MAF sensor
4
Vacuum leak at a hose, PCV fitting, or brake booster line
Medium severity
A cracked or disconnected vacuum hose unmetered by the MAF is one of the most common causes of a lean condition on any port-injected engine.
Common cause
Parts:vacuum hose PCV valve
5
Clogged fuel filter
Medium severity
A restricted filter starves the injectors under higher demand, producing the same lean signature as a weak pump.
Common cause
Parts:fuel filter
6
Exhaust leak upstream of the front (fuel-trim) O2 sensor
Medium severity
Outside air drawn in through a manifold or header-pipe leak skews the upstream O2 reading lean even when the actual mixture is correct.
Common cause
7
Stuck-open PCV valve
Low severity
A PCV valve stuck open admits excess unmetered air into the intake, a classic and inexpensive-to-fix source of a lean code.
Common cause
Parts:PCV valve

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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