How much does it cost to fix P0172 on a Honda?

Repair costs for P0172 on Honda vehicles typically range from $120 to $600 depending on the underlying cause. The most common fix is: A contaminated or failing mass airflow (MAF) sensor causing the ECU to overestimate incoming air and over-fuel..

Honda Check Engine Code

P0172 on Honda

System Too Rich (Bank 1)

Severity: medium DIY difficulty: 2/5 Honda cost: $120–$600

Last updated April 30, 2026 Also covers: Acura

P0172 on Honda: what makes it different

Honda's fuel trim system flags P0172 when the engine computer has to keep pulling fuel to compensate for a mixture that's running richer than commanded, and it shows up across Honda's four-cylinder and V6 lineup for a mix of sensor, PCV, and (on newer turbo engines) carbon/oil-dilution related reasons.

Most-affected engines

K24 2.4L I4 (Accord, CR-V, Civic Si)
J35 3.5L V6 (Pilot, Odyssey, Ridgeline)
L15B7 1.5L Turbo (Civic, CR-V, Accord)

Common model years: 2013–2022

Most likely cause on Honda

A contaminated or failing mass airflow (MAF) sensor causing the ECU to overestimate incoming air and over-fuel.

Known Honda engine-family issues

Honda's 1.5L turbo four-cylinder (used widely in Civic, CR-V, and Accord) has a well-documented tendency toward fuel dilution of the engine oil in cold climates or on short-trip driving patterns, which can indirectly affect combustion efficiency and trigger rich-condition codes. The J35 V6 and K24 four-cylinder are generally reliable but accumulate carbon and PCV wear with age, which is the more common driver of P0172 on those engines.

Honda-specific causes (most common first)

Dirty or aging MAF sensor sending an inaccurate airflow signal
Failing primary oxygen (A/F) sensor giving a false lean signal that triggers extra fueling
Stuck-open EVAP purge valve pulling raw fuel vapor into the intake at idle
Clogged or degraded PCV valve/hose allowing excess crankcase vapor into the intake
On 1.5L turbo engines, oil dilution from fuel not fully burning off during short trips, which can skew mixture readings
Leaking or worn fuel pressure regulator over-supplying the fuel rail

Honda-specific diagnostic tip

On Honda OBD-II systems, check both short-term and long-term fuel trims on Bank 1 with a scan tool before replacing parts — if long-term trim is significantly negative at idle but improves at highway speed, suspect the PCV system or a vacuum leak feeding raw fuel vapor rather than the MAF sensor itself.

Symptoms drivers report

Check engine light
Strong fuel smell
Black smoke from exhaust under load
Fouled spark plugs
Poor fuel economy
Rough idle

Typical repair cost on Honda

Most Honda owners fix P0172 for between $120 and $600, depending on which underlying cause turns out to be at fault. Start with the most-likely cause for your vehicle — A contaminated or failing mass airflow (MAF) sensor causing the ECU to overestimate incoming air and over-fuel. — before throwing parts at it.

Honda P0172 FAQ

Does P0172 mean my Honda 1.5L turbo has the oil dilution problem?

Not necessarily. P0172 is a fuel trim code, not a direct oil-dilution alert. However, on short-trip-driven 1.5L turbo Hondas, check your oil level and smell for a fuel odor on the dipstick as part of your diagnosis, since dilution can be a contributing factor.

Can a dirty air filter cause P0172 on a Honda?

Indirectly, yes — a heavily clogged filter can distort the MAF sensor's readings, but a full-blown P0172 is more often the MAF sensor itself, a purge valve, or the PCV system rather than the filter alone.

Is it safe to keep driving my Honda with a P0172 code?

Short term, yes, but a persistently rich mixture wastes fuel, can foul spark plugs, and may damage the catalytic converter over time, so it's worth diagnosing within a couple weeks.