Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
VECI Acronym Definitions
ALVW-Adjusted Loaded Vehicle Weight, (Curb Weight + GVWR) /2.
Averaging Bank/Trade-Used for Nox Credits on Heavy Duty Trucks Only.
BBL-Barrel.
CALIFORNIA ARB-California Air Resource Board.
CARB-California Air Resource Board.
CARB LEV-Low Emission Vehicle.
CARB TLEV-Transitional Low Emission Vehicle.
CARB ULEV-Ultra Low Emission Vehicle.
CARB ZEV-Zero Emission Vehicle.
CPI-Central Port Injection.
CI-Cylinder Injection.
CNG-Compressed Natural Gas.
EPA-Environmental.
EVAP-Evaporative Emissions.
GVW-Gross Vehicle Weight.
GVWR-Gross Vehicle Weight Rating, Curb weight plus payload.
HHDE-Heavy Heavy Duty Engine.
HHDDE-Heavy Heavy Duty Diesel Engine.
MHDE-Medium Heavy Duty Diesel Engine.
MPI-Multi Port Injection.
LDDT-Light Duty Diesel Truck categories.
LDT-Light Duty Truck (gasoline) categories based on weight as defined in the table.
LDV-Light Duty Vehicle, generally passenger cars and light trucks under 6000 pounds GVWR.
LHDE-Light Heavy Duty Engine (several weight categories).
LVW-Loaded Vehicle Weight, curb weight plus 300 pounds.
MDT-Medium Duty Truck categories based on weight as defined in the table.
MDV-Medium Duty Vehicle.
MHDE-Medium Heavy Duty Engine.
MY-Model Year.
NCP-Non Compliance Penalty.
OBD-On-Board Diagnostic.
ORVR-On-Board Refueling Vapor Recovery.
PC-Passenger Car.
SI-Sequential Injection.
SULEV-Super Ultra Low Emission Vehicle.
Tier 0-California and Federal regulations effective prior to Tier 1 phase in dates.
Tier 1-California regulations beginning in 1993 model year and Federal regulations beginning in 1994 model year.
TBI-Throttle Body Injection.
LEV-Low Emission Vehicle.
ZEV-Zero Emission Vehicle.
ULEV-Ultra Low Emission Vehicle.
ILEV-Inherently Low Emission Vehicle.
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.