P0171 on a 2015 Honda Accord Plug In 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 Plug In Hybrid

Ranked from 609 NHTSA owner complaints filed for this vehicle.

Sort by:

1
Weak or failing high-pressure fuel pump
High severity
Multiple owners report DTC P0087 (fuel rail pressure too low) and stalling/power-loss tied to the 2013-17 Accord fuel pump module recall — a direct cause of a lean-running engine.
Reported in 6 NHTSA complaints
Parts:fuel pump fuel pump module
2
Deteriorated intake manifold plenum causing a vacuum leak
Medium severity
This vehicle's intake manifold plenum is documented as corroding and breaking down over time, causing vacuum leaks that lean out the mixture.
Reported in 1 NHTSA complaint
Parts:intake manifold gasket
3
Dirty or failing MAF sensor
Medium severity
A contaminated or drifting MAF under-reports intake air, causing the PCM to under-fuel.
Common cause
Parts:mass air flow sensor
4
Stuck-open PCV valve
Medium severity
A PCV valve stuck open draws excess unmetered air into the intake, leaning the mixture.
Common cause
Parts:PCV valve
5
Exhaust leak upstream of the oxygen sensor
Low severity
Outside air drawn in ahead of the sensor is read as a lean exhaust condition.
Common cause
Parts:exhaust gasket
6
Clogged fuel filter restricting flow
Medium severity
Restricted fuel delivery under load reduces rail pressure and leans the mixture during acceleration.
Common cause
Parts:fuel filter

Part links go to Amazon search results for this vehicle. As an Amazon Associate, WrenchConnect earns from qualifying purchases — always confirm fitment for your exact trim and engine before ordering.

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