Toyota check engine codes
Overview
Toyota engines are known for durability, but EVAP leak codes, catalytic converter codes at high mileage, and lean codes from MAF or vacuum leaks are common.
Codes notably common on Toyota
- P0420 Catalyst System Efficiency Below Threshold (Bank 1) · Toyota notes
- P0171 System Too Lean (Bank 1) · Toyota notes
- P0455 Evaporative Emission System Large Leak Detected · Toyota notes
- P0456 Evaporative Emission System Very Small Leak Detected · Toyota notes
- P0442 Evaporative Emission System Small Leak Detected
- P0128 Coolant Thermostat (Coolant Temperature Below Regulating Temperature)
- P0300 Random or Multiple Cylinder Misfire Detected
Toyota specific notes
- Toyota service guidance for EVAP leak codes starts with a genuine Toyota cap, hose inspection, and a smoke test. Toyota TSB EG045-07 covered charcoal canister failures on certain 2005 to 2007 Tacoma trucks.
- Many Toyota models use an air fuel ratio sensor upstream instead of a traditional oxygen sensor, so live data and heater codes may look different.
Owner's manuals
Official Toyota owner's manual / owner portal (manufacturer site; we do not host copies).
Repair manuals
Step-by-step service manuals for Toyota with torque specs and wiring diagrams:
Haynes manuals for Toyota Chilton manuals
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Recall lookup
Check open Toyota recalls with your VIN at the NHTSA recall lookup.
Sources
- https://www.vehicleservicepros.com/tsbs/article/53091486/toyota-evap-dtcs-2012-08-21
- 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 Toyota as on any vehicle:
P0430 P0301 P0302 P0303 P0304 P0174 P0440 P0135 P0141 P0101 P0299 P2135 P0401