VEIP - Vehicle Not Passing


The Vehicle Emissions Inspection Program (VEIP) describes the steps you need to take when your vehicle does not pass the VEIP tests. ​

Why didn't my vehicle pass the VEIP emissions test(s)?


There are many reasons why your vehicle may have not passed the test(s). The most common are:

  1. Hydrocarbon (HC) failure
  2. Carbon monoxide (CO) failure
  3. Sample dilution failure
  4. On-board diagnostic (OBD) failure
  5. Emission control equipment was removed or altered
  6. Gas cap failure

Reasons Why Vehicle Did Not Pass
And Possible Causes

Reason Possible Causes

Hydrocarbon (HC) failure- exceeds established standards for hydrocarbon


Air to fuel mixture may be too lean or too rich.


Positive Crankcase Ventilation (PCV) valve may not be functioning properly (if equipped).


Vacuum leak in the system.


Exhaust Gas Re-Circulation (EGR) system may not be functioning properly (if equipped).


Ignition timing may not be properly set.


One or more spark plugs may not be performing as they should.


Catalytic converter may be partially clogged or not properly functioning.


Ignition system parts are not working properly.


Internal engine parts or equipment may not be functioning.


Various engine sensors may not be functioning.

Carbon monoxide(CO) failure- exceeds established standards for carbon monoxide


Air to fuel mixture may be too rich.


Idle speed is not correct.


Air filter may be partially clogged.


Choke may not be operating properly.


Positive Crankcase Ventilation (PCV) valve may not be functioning properly.


Air or fuel problems, other equipment or engine malfunctions.


Catalytic converter may be partially clogged or not properly functioning.


Engine oil may be dirty and needs changing.


Various engine sensors may not be functioning.

Sample dilution failure 


The CO + CO2 measurement was less than 6%, indicating that a valid exhaust sample could not be taken from the vehicle.


The vehicle has leaks in the exhaust system or improper engine adjustments.

On-board diagnostic (OBD) failure- OBD system identified Diagnostic Trouble Codes (DTC) or a Faulty Malfunction Indicator Light (MIL)


The vehicle’s on-board diagnostic system has identified one or more emissions control components that are malfunctioning.


The vehicle’s Malfunction Indicator Light (MIL) on the dashboard is not functioning properly.

Emissions control equipment


If the emissions control equipment is not present or has been disconnected the vehicle will not pass the inspection.

Gas capfailure


The gas cap does not fit properly and could be leaking vapors.


Gas cap is not sealing tightly.

What do I need to do now?


You should have your vehicle repaired and re-tested as soon as possible. Be sure to show the person repairing your vehicle your Vehicle Emissions Inspection Certificate (VEIC) and diagnostic report. If your vehicle is under warranty, you may want to have the dealer perform the needed repairs. Otherwise, you can use any mechanic, or you may do the repairs yourself. Note that certain repair facilities are certified to perform emissions work and offer approved emissions analyzers, On-Board Diagnostic (OBD) scan tools and trained personnel.

Note:  OBD re-test - Drive vehicle in a normal manner for one (1) week before re-test to allow enough time for monitors to reset themselves.

After your vehicle is repaired you can have it re-tested at any of the 18 VEIP stations located throughout Maryland. The first re-test of your vehicle is free.

Do I need to have my vehicle re-tested if it did not pass the initial VEIP emissions test?


You must have your vehicle re-tested until it passes the required VEIP tests or until you receive a repair waiver. To be eligible for the waiver you must have made emissions-related repairs to your vehicle totaling at least $450.00. The cost of an emissions-related repair can be counted if it was made:

  • during the 30 days before the initial VEIP test; or,
  • on the day of the initial VEIP test; or,
  • during the period following the initial VEIP test and prior to the last failed test.

To apply for the repair waiver, you also must complete and submit to the VEIP station the repair waiver request (on the reverse side of the vehicle emissions inspection certificate) and the original invoices, receipts and/or repair orders for the emissions-related repairs. A Station Representative will visually inspect your vehicle to verify that all emissions equipment is present and that the repairs you paid for were completed.

Federal and state laws may not allow the costs of repairs to the exhaust system, beyond the catalytic converter, to count toward the expenditure requirement for a repair waiver. Repair waivers are not issued if any emission control devices are disconnected or removed.

If you have not spent at least $450.00 on repairs at the time of re-testing, your vehicle will need to be repaired again and undergo another test. You will be charged for each additional re-test, after the first re-test which is free.


  • The first re-test of a vehicle’s emissions (following repairs) is free if done by the “valid through” date on the VEIC.
  • The fee for each additional re-test of a vehicle’s emissions is the same as the original VEIP test fee.
  • late fee is assessed after the “valid through” date has passed.
  • After the initial late fee is assessed, an additional late fee is charged for every four-week period (28 days) that the vehicle continues to be late for re-testing.

Contact Inf​ormation:

Maryland Motor Vehicle Administration

6601 Ritchie Highway, NE
Glen Burnie, MD 21062

For telephone questions:
Vehicle Emissions Inspection Program:       1-410-768-7000
MVA Customer Service Center:                       1-410-768-7000
TTY/Hearing Impaired:                                        1-301-729-4563