Chevrolet check engine codes
Overview
Chevrolet vehicles have some of the best documented code patterns because they are so common. EVAP leaks, lean codes from intake gasket leaks, cylinder deactivation misfires, and turbo underboost on small engines lead the list.
Codes notably common on Chevrolet
- P0171 System Too Lean (Bank 1) · Chevrolet notes
- P0174 System Too Lean (Bank 2) · Chevrolet notes
- P0300 Random or Multiple Cylinder Misfire Detected · Chevrolet notes
- P0420 Catalyst System Efficiency Below Threshold (Bank 1) · Chevrolet notes
- P0455 Evaporative Emission System Large Leak Detected · Chevrolet notes
- P0442 Evaporative Emission System Small Leak Detected
- P0128 Coolant Thermostat (Coolant Temperature Below Regulating Temperature)
- P0299 Turbocharger or Supercharger Underboost · Chevrolet notes
- P0101 Mass Air Flow (MAF) Sensor Circuit Range/Performance
Chevrolet specific notes
- A pending class action alleges lifter failures in 2014 and later GM 5.3, 6.0, and 6.2 liter V8 engines with Active or Dynamic Fuel Management. Reported symptoms include ticking, misfires, and rough running. These are allegations; GM disputes them.
- GM issued a service bulletin for 2019 and later Silverado (and Sierra) trucks where dust plugs the EVAP canister and vent solenoid, setting P0449 or P0455. The fix adds a vent filter.
- GM issued guidance on 1.4 liter turbo engines (Cruze, Sonic, Trax, Encore) for oil consumption and PCV system faults, which owners and shops connect to lean and boost codes.
- Older GM 3.1 and 3.4 liter V6 engines are known for lower intake manifold gasket failures that leak coolant.
Owner's manuals
Official Chevrolet owner's manual / owner portal (manufacturer site; we do not host copies).
Repair manuals
Step-by-step service manuals for Chevrolet with torque specs and wiring diagrams:
Haynes manuals for Chevrolet Chilton manuals
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Recall lookup
Check open Chevrolet recalls with your VIN at the NHTSA recall lookup.
Sources
- https://www.gmlifterlawsuit.com/
- https://www.carcomplaints.com/news/2026/gm-lifter-lawsuit-update.shtml
- https://static.nhtsa.gov/odi/tsbs/2023/MC-10239087-0001.pdf
- https://dot.report/bulletins/10114424
- https://www.enginebuildermag.com/2003/07/coolant-contamination-of-engine-oil-for-1996-2003-gm-3-1l-or-3-4l-vin-j-e-engines/
- 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 Chevrolet as on any vehicle:
P0430 P0301 P0302 P0303 P0304 P0440 P0456 P0135 P0141 P2135 P0401