Honda check engine codes

Overview

Honda engines are generally durable. Catalytic converter efficiency codes, misfires (some covered by Honda warranty extensions), and EVAP small leaks appear frequently.

Codes notably common on Honda

• P0420 Catalyst System Efficiency Below Threshold (Bank 1) · Honda notes
• P0300 Random or Multiple Cylinder Misfire Detected · Honda notes
• P0301 Cylinder 1 Misfire Detected
• P0302 Cylinder 2 Misfire Detected
• P0303 Cylinder 3 Misfire Detected
• P0171 System Too Lean (Bank 1)
• P0456 Evaporative Emission System Very Small Leak Detected
• P0141 O2 Sensor Heater Circuit Malfunction (Bank 1 Sensor 2)

Honda specific notes

• Honda has extended warranty coverage on some engines for misfires (P0301 to P0304) caused by piston ring sticking that leads to oil fouled spark plugs. One example is a bulletin covering certain Odyssey models. Ask a dealer to check your VIN for open coverage.
• Valve clearance inspection is a scheduled maintenance item on many Honda engines; check your maintenance schedule.

Owner's manuals

Official Honda owner's manual / owner portal (manufacturer site; we do not host copies).

Recall lookup

Check open Honda recalls with your VIN at the NHTSA recall lookup.

Sources

• https://static.nhtsa.gov/odi/tsbs/2025/MC-11022768-0001.pdf
• https://www.nhtsa.gov/recalls

Sources checked October 2026. Bulletins apply only to the models and years they list.

All other codes

These work the same on Honda as on any vehicle:

P0430 P0304 P0174 P0440 P0442 P0455 P0128 P0135 P0101 P0299 P2135 P0401