Dealer Message - American Honda Motor Co., Inc. (AHM) is searching for certain 2018 Fits with customer complaint of Check Engine Light (CEL) on with DTC P0420 [Catalyst System Efficiency Below Threshold] stored. To better understand the cause of this condition, AHM would like to inspect the vehicle prior to your attempting a repair of any kind.
full bulletin at NHTSA ↗2018 Honda Fit engine problems
moderate Owners of the 2018 Honda Fit have filed 12 NHTSA complaints about the engine at roughly $3,100 to repair (U.S. federal records, as of July 2026). Source: NHTSA Office of Defects Investigation. See engine across all vehicles →
Complaints
12
Recalls
0
Avg fix
$3,100
| Model year | engine complaints |
|---|---|
| 2015 Fit | 25 |
| 2016 Fit | 4 |
| 2017 Fit | 6 |
| 2018 Fit (this page) | 12 |
| 2019 Fit | 12 |
| 2020 Fit | 5 |
Is there a fix? Manufacturer service bulletins
The manufacturer has issued service bulletins covering engine on this vehicle — documented repair instructions, service campaigns, or warranty extensions sent to dealers. A TSB isn't a recall (it's not a free safety remedy), but it's the manufacturer acknowledging the issue and how to fix it.
Dealer Message - American Honda Motor Co., Inc. (AHM) is searching for certain 2018 Fits with customer complaint of Check Engine Light (CEL) on with DTC P0420 [Catalyst System Efficiency Below Threshold] stored. To better understand the cause of this condition, AHM would like to inspect the vehicle prior to your attempting a repair of any kind.
full bulletin at NHTSA ↗Dealer Message - American Honda Motor Co., Inc. (AHM) is searching for certain 2017-2018 Fits with customer complaint of Check Engine Light (CEL) on with DTC P0420 (Catalyst System Efficiency Below Threshold) stored. To better understand the cause of this condition, AHM would like to collect specific parts from the vehicle prior to your attempting a repair of any kind.
full bulletin at NHTSA ↗Dealer Message - American Honda Motor Co., Inc. (AHM) is searching for certain 2017-2018 Fits with customer complaint of Check Engine Light (CEL) on with DTC P0420 (Catalyst System Efficiency Below Threshold) stored. To better understand the cause of this condition, AHM would like to collect specific parts from the vehicle prior to your attempting a repair of any kind.
full bulletin at NHTSA ↗Dealer Message - American Honda Motor Co., Inc. (AHM) is searching for certain 2017-2018 Fits with customer complaint of Check Engine Light (CEL) on with DTC P0420 (Catalyst System Efficiency Below Threshold) stored. To better understand the cause of this condition, AHM would like to collect specific parts from the vehicle prior to your attempting a repair of any kind.
full bulletin at NHTSA ↗Source: NHTSA manufacturer communications. Bring the bulletin number to your dealer or shop.
The failure pattern owners describe
Owners of 2018 Honda Fits report two main engine problems that dealers struggle to diagnose consistently.
The first centers on carbon buildup on intake valves and fuel injector failures tied to the direct injection engine design. Check engine lights start appearing at 31,000 miles and beyond, often accompanied by hesitation, shaking, or multiple warning lights. Dealers have diagnosed P0300, P0304, P0420, P0172, and P2198 codes—sometimes in sequence on the same vehicle. One owner replaced ignition coils and a catalytic converter for $885, only to get a check engine light 48 hours later. Another paid $2,605 for four fuel injectors at 75,000 miles. The frustration: problems recur despite repairs, and dealers disagree on whether carbon cleaning or injector replacement is the fix. Some refuse to clean carbon if buildup appears minimal. Honda issued an extended warranty for carbon buildup and misfires on certain 2018 Fits, but coverage gaps remain—catalytic converters fall under emissions warranty while coils do not.
The second issue is a grinding or rattling noise from the VTC (Variable Valve Timing) actuator during cold starts, typically heard at 55,000 miles and beyond. No warning lights appear. Dealers acknowledge the noise but refuse to repair it, even though other Honda models have recalls for the identical problem. Owners feel this inconsistency signals a design flaw Honda has sidestepped on the Fit.
Same Honda Fit engine reports on nearby years: 2015 · 2019
Failure modes owners describe
Carbon buildup on intake valves and fuel injector failures
Excessive carbon deposits accumulate on intake valves in the direct injection engine, often accompanied by fuel injector failure. This causes check engine lights, hesitation, shaking, and misfire codes. The problem recurs even after injector replacement, and dealers disagree on root cause—some blame carbon buildup, others claim failed injectors. Carbon cleaning is sometimes refused if carbon buildup is deemed insufficient, leaving owners in a diagnostic loop.
When: 31,000 to 110,000 miles; some owners report repeated occurrences within months or years
Symptoms owners cite: Check engine light (intermittent or persistent); Hesitation and shaking while driving; Multiple warning lights (TPMS, Vehicle Stability Assist, Electric Power System); Engine running smoothly despite warning lights; Problem recurs after repairs
Codes mentioned: P0300 (Random/Multiple Cylinder Misfire), P0304 (Cylinder 4 Misfire), P0420 (Catalyst System Low Efficiency), P2198 (Oxygen Sensor Circuit High Voltage), P0172 (System Too Rich)
Repairs/costs cited: Fuel injectors $2,605 for four injectors; spark plugs, ignition coils, and catalytic converter replacement ($885 for coils and converter combined); carbon cleaning $500–$604. Repairs often don't resolve the underlying issue.
Recalls/TSBs owners mention: Extended warranty and warranty extension letter for certain 2018 Fits covering carbon buildup and misfires (TSB/recall referenced). Catalytic converter covered under emissions warranty; ignition coils not covered. Some dealers offer one-time courtesy repairs; others refuse to perform carbon cleaning if buildup is deemed insufficient.
VTC actuator grinding noise at cold start
Variable Valve Timing (VTC) actuator produces a grinding or rattling clink noise, particularly during cold morning starts. Noise is audible but no warning lights appear. Dealerships downplay the symptom as not a problem despite it being a known issue on other Honda models with recalls.
When: 55,000 miles and beyond; ongoing since purchase in some cases
Symptoms owners cite: Grinding/rattling/clink noise from engine at cold start; Noise especially pronounced on cold mornings; No warning lights
Recalls/TSBs owners mention: Dealerships acknowledge the noise but refuse to diagnose or repair, claiming it is not a problem. Other Honda models have recalls for the same issue, but 2018 Fit owners report being denied similar coverage.
Synthesized from 12 NHTSA owner complaints — unverified consumer allegations, summarized for patterns. The verbatim filings appear below.
What owners are reporting 0 most recent
Had engine trouble with your 2018 Honda Fit?
File a complaint with NHTSA → It's free, official, and how every report above got here — owner filings are the federal safety record this page is built on.
Common questions
How serious is the engine problem on the 2018 Honda Fit?
It's a documented issue but not catastrophic. 12 complaints have been filed. Repairs average $3,100 and most owners catch it before it causes a breakdown.
At what mileage does the engine typically fail?
Based on the 12 complaints filed, engine issues most often appear around 82,500 miles. Some report problems earlier; some make it well past 150,000 with no symptoms. Maintenance habits matter — vehicles that received timely fluid services and were not regularly overworked tend to last longer.
What does it cost to fix?
Independent shops typically charge around $3,100 for engine repairs on this vehicle. Dealer pricing tends to run 20-40% higher. The exact figure depends on the specific failure mode, parts availability, and your local labor rates. If you're outside factory warranty, an extended service contract often covers this category.
Are there any recalls related to engine?
No active recalls currently cover engine issues on this vehicle. The complaints filed represent owner-reported failures that haven't risen to the level of a manufacturer-issued recall — but they're still worth knowing about before you buy or budget for repairs.
Related
Complaint and recall data sourced from the National Highway Traffic Safety Administration (NHTSA)
public records database. Verify the raw federal record at
nhtsa.gov/vehicle/2018/Honda/Fit.
Severity ratings are derived from reported crashes, fires, injuries, and fatalities. Repair cost estimates are
independent-shop national averages and may differ in your area. Some links on this page are affiliate links.