Diesel Smog Test Information

The new diesel smog test will apply to all 1998 and newer diesel powered vehicles under 14,000 GVWR. Diesel testing is implemented as a biennial program similar to the regular smog check program.

Diesel Inspection Procedure:
    1.    Visual Test
    2.    OBD II Test
    3.    Visible Smoke Test

.Visual Check:
    1.    Crankcase Depression Regulator CDR) or Positive Crankcase Ventilation (PCV)
    2.    Diesel Oxidation Catalyst (DOC)
    3.    Diesel Particulate Filter (DPF)
    4.    Nox Absorber
    5.    EGR
    6.    Fuel Injection
    7.    Temperature and Pressure Sensors
    8.    Wiring of Sensors/Switches/Computers
    9.    Vacuum Line Connections to Sensor/Switches
    10.    Other Diesel Emission-Related Components: Turbo/Supercharger, Exhaust/Intake, etc.

.OBD II Check:
    1.    "Check Engine Light" (MIL) is Operational
    2.    MIL on/off
    3.    OBD Readiness Status Codes

Visible Smoke Test:
    1.    Idle Test
    2.    Idle Crankcase (CDR/PCV) Test
    3.    Snap Test

Subpages (1): Diesel FAQ