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Emissions Inspection Results Information

What is OBDII and how does it work? [Back to Top]
The first on-board diagnostic (OBD) systems were introduced in the early 1980's to lower vehicle emissions and help automotive repair technicians in the diagnostics and repair of computerized engine controls. As a results of improved technology, a new generation of OBD (OBDII) was developed for 1996 and newer vehicles. The new OBDII systems monitor the vehicle's electronic sensors and actuators while the vehicle is being driven to insure they are working "as designed" by the manufacturer. The on-board computer has the ability to identify a problem well before the driver is aware of any problems, such as lack of performance, high emissions, or poor fuel economy. Early detection helps avoid costly repairs and can improve the vehicle's emissions.

How is the driver notified? [Back to Top]
A light on the dash, called a Malfunction Indicator Lamp (MIL), will illuminate if an emissions related problem is detected. There is no standard MIL symbol below are some examples used by manufacturers.


Your vehicle's OBDII system will turn the MIL light "ON" when it finds a fault that may cause high engine or evaporative emissions. In some instances, this may mean that immediate service is needed to prevent expensive damage and ultimately, high emissions. (Check your owner's manual for detailed information.)

Do I have to go to the dealer to get my OBDII car fixed? [Back to Top]
No. Properly trained and equipped independent repair shops are capable of utilizing the diagnostic information from the OBDII system and can make repairs just like dealers. In fact, several of the provisions incorporated in the OBDII regulation are intended to make it easier for independent shops to diagnose and repair vehicles accurately and in a cost-effective manner. The Federal Clean Air Act requires that catalytic converters and Onboard Diagnostic devices on 1995 and newer vehicles be warranted for a minimum of 8 years or 80,000 miles.

What does a North Carolina emissions inspection consist of? [Back to Top]
A North Carolina emissions inspection consists of connecting a certified analyzer to the vehicle's OBDII system to verify that all vehicle emissions components/systems are working per the manufacturer specifications along with a visual safety/tamper inspection.

My Check Engine light is on, what does that mean? [Back to Top]
Most manufacturers advise having the vehicle serviced as soon as conveniently possible. Since there are many different problems that can cause the light to illuminate, it is hard to generalize how severe a problem may be. However, often the problem will have a noticeable effect on fuel economy, performance, or drivability of your vehicle, and extended driving without fixing the problem could possibly damage other components. Additionally, there are certain malfunctions that can cause the warning light to blink. This indicates that a malfunction is currently occurring which could be damaging your catalytic converter. Because replacement of the catalyst can be expensive, many manufacturers recommend having the vehicle serviced as soon as possible.

I failed my emissions inspection.

My MIL (check engine) light did not come on. What do I do now? [Back to Top]
The inspector mechanic is required to verify the MIL light bulb is working by turning on the key without starting the engine. A bulb not working as a result of being burned out bulb or due to a blown fuse will cause you to fail the emissions inspection.

My check engine light was on. What do I do now? [Back to Top]

  • Your check engine light illuminated indicating something has been detected outside the manufacturer's specifications in your vehicle's emissions control system. Your Vehicle Inspection Receipt/Statement (VIRS) will list Diagnostic Trouble Codes (DTCs) that indicate the general area of the emission control systems that do not pass inspection.
  • If the check engine light remains on, you will need to have the problem properly diagnosed and your vehicle repaired prior to retest. The retest is free if you return to the original inspection station within 60 days.
  • Make sure to allow ample driving time after repairs for the vehicle to complete it's drive cycle and the OBDII computer to become "Ready" for testing (1-2 weeks, including some highway driving).
  • Motorists should beware of offers to turn the "Check Engine" light off in an attempt to pass the OBD II test without making repairs. If the light has been turned off without making necessary emission-related repairs, it will come back on and the vehicle will not pass the test. The vehicle will be rejected for being "Not Ready."
  • Contact your vehicle manufacturer or repair technician and inquire about Recalls, manufacturer applied Extended Warranties, and Technical Service Bulletins (TSBs) regarding the emission control system (research by your VIN).

My vehicle was rejected for being "Not Ready", what does that mean? [Back to Top]
On-Board Diagnostic II systems (OBDII) perform self-tests of their various emissions system components utilizing various monitors while the vehicle is driven. Therefore a vehicle that has received a North Carolina emissions inspection result of "not ready" due to recent maintenance or vehicle's battery replacement or disconnection must be driven to reset monitors to a ready status. These components are referred to as "readiness monitors" and identify whether the vehicle's computer has meet the vehicle manufacturer "enable criteria" conditions to run the required "diagnostic tests".

The following are suggestions that may help get your monitors to a "Ready" status:

  • Drive your vehicle for several days under normal conditions including some highway driving at the speed limit.
  • Contact your vehicle manufacturer or repair technician and inquire about Recalls, manufacturer applied Extended Warranties, and Technical Service Bulletins (TSBs) regarding the emission control system (research by your VIN).
  • Make sure all thermostats and fuses are working properly.
  • If your vehicle has had an after-market radio, CD player or security system installed, make sure that the wiring is not interfering with connection to the vehicle's computer or battery system.
  • Have a diagnostic analysis performed using an OBDII Generic Scan Tool.
  • You may be able to obtain a copy of your vehicle's "drive cycle" from your vehicle manufacturer. You may also find information regarding your vehicle's "drive cycle" in the owner's manual.

My vehicle will not communicate, what does that mean? [Back to Top]
Communications between the certified emissions analyzer and your vehicle could not be established. Below are several suggestions that could be followed to ensure you receive a North Carolina emissions inspection:

  • The inspector-mechanic should attempt to test the vehicle at least three times.
  • If your vehicle has had an after-market radio, CD player or security system installed, make sure that that the wiring is not interfering with connection to the vehicle's computer or battery system.
  • Research vehicle recalls, technical service bulletins (TSBs) and manufacturer applied extended warranties to determine if there are any recommended repairs regarding the emission control system.
  • Have a diagnostic analysis performed using an OBD Generic Scan Tool.
  • Contact your local DMV district office and they can check your vehicle for communications using their scan tool (DMV District office locations ).

What is a drive cycle? [Back to Top]
Vehicles equipped with an On-Board Diagnostic II (OBDII) perform self-test of their emission system utilizing various monitors while the vehicle is driven. These tests are referred to as "readiness monitors" and identify whether the vehicle's computer has meet the vehicle manufacturer "enable criteria" condition to run the required "diagnostic tests".
  Your everyday driving patterns over a period of time should be sufficient to set all the monitors. If a North Carolina emissions inspection is required and your vehicle's battery is replaced or emission repairs were completed, the monitors will be set to "not ready" status. In this situation, your everyday driving pattern may not be sufficient to set required monitors in a short period of time. Therefore a manufacturer's "drive cycle" must be driven. This "drive cycle", which should not be performed by inexperience drivers, is designed to allow monitors to operate in a compressed time and distance drive pattern. The correct drive cycle for your vehicle can vary greatly depending on the vehicle model and are available from most auto manufacturers.

My check engine light is on and my annual emissions inspection is due. Should I get my vehicle repaired before bringing it in for an emissions inspection? [Back to Top]
If your emission inspection is due soon, have the vehicle inspected first. The vehicle will fail due to the MIL light being commanded on, but you will receive the Vehicle Inspection Receipt/Statement (VIRS), which will document the cause of the failure. You can then provide this information to your repair technician (repairs must be made within 60 days of the initial failure to receive a free re-inspection). If the vehicle then returns for re-inspection and fails a second time, you may be eligible for one-year waiver from DMV. See the question dealing with waivers qualifications below.

What does the gas cap have to do with emissions? [Back to Top]
If your gas cap is damaged or not tightened per manufacturer requirements, this will allow excess evaporative emissions to escape from the vehicle causing the evaporative monitor to set the MIL light. Corrective action would be to replace the gas cap if damaged, but most cases retightening will solve the problem.

How do I get a waiver? [Back to Top]
Waivers are available for vehicles unable to pass an emissions inspection test and are granted by authorized DMV personnel. A vehicle receiving a waiver is exempted from meeting the full requirements of the emissions test portion of the inspection for one year. For more information concerning waivers please contact your local DMV Office .

  1. Parts Waivers
     
    A parts waiver can be issued if an emission control devices has either been tampered or is inoperative and the part is no longer available.
     
    The vehicle owner must produce three (3) forms of documentation from a dealership, automotive part store, and salvage yard supporting the claim the part is no longer available. This documentation must be signed on the company letterhead.

  2.  
  3. Repair Waivers
     
    A repair waiver can be issued when a vehicle cannot pass an emission inspection but the owner has made the attempt in correcting the emission failure. The following are the basic steps that need to be followed in order to be eligible for a repair waiver. The "OBDII Failure Brochure" which describes the repair waiver in more detail can be provided to you upon request from your inspection facility.
     
    1. Vehicle fails the emissions inspection test, that is, fails the analysis of data provided by the On-Board Diagnostic (OBDII) equipment, but has passed the visual and safety portion of the inspection.
    2. The vehicle owner takes vehicle in for repairs and the repair facility provides a repair receipt listing the OBDII trouble codes that resulted in the emission inspection failure, itemizing the repairs costing at least $200.00 made to the vehicle to correct the OBDII failure. NOTE: Repairs are to be made after vehicle fails an emission inspection.
    3. The vehicle owner must take the vehicle that failed the emission inspection, the two failed emission inspection records (VIRS), and the original repair receipts to the local DMV office.
    4. DMV will review all documentation and inspect the vehicle for the repairs before a waiver can be issued.

  4. Non-Communication Waivers
     
    A non-communication waiver can be issued if a vehicle fails the OBDII emissions inspection because the vehicle failed to communicate with the approved state analyzer, but has passed the visual and safety inspections.
     
    1. The vehicle fails the OBDII emission test due to non-communication, but has passed the safety and tamper portions of the inspection.
    2. Owner takes the vehicle to the local DMV Office to be tested with an independent scan tool.
    3. If vehicle does not communicate with the scan tool, a non-communications waiver cannot be issued and the vehicle will need to be taken in for repairs. NOTE: The repair waiver process, as discussed earlier, will then be enforced.
    4. If the vehicle does communicate with the scan tool, the OBDII pass/fail requirements will then be applied to the scan tool test results and a waiver can then be issued.

  5. Not Ready Waivers
     
    In order to receive an emission inspection the vehicle's OBD monitors must be in a "ready" state. If a vehicle has too many "not ready" monitors, the vehicle will be rejected from receiving an emission inspection and receive a Not Ready Rejection VIRS. The vehicle must be driven in order to set the OBDII monitors to a "ready" state. Some vehicles become ready very easily while some are more difficult to become "ready".
     
      Acceptable limit of not-ready monitors are:
       
    1. 2 - for all 1996-2000 model year vehicles
       
    2. 1 - for all 2001 and newer model year vehicles

    There are different scenarios when a not-ready waiver can be issued. Please contact your local DMV office for specific information. Below are the general procedures for the not ready waiver.
     
    1. The vehicle is rejected from receiving an emission inspection because it has too many "not ready" monitors, exceeding the acceptable limit.
    2. The customer attempts to get the vehicle's monitors to set by performing any of the following steps.
       
      1. Repairs, and/or
      2. Normal Driving (daily driving habits, i.e. trips to store, work, activities, road trips, etc), and must be documented by a reasonable mileage change between the first and last VIRS or
      3. A manufacturer's drive cycle may be conducted in place of driving the vehicle for several days. The drive cycle performed must be presented to DMV personnel.

    3. The vehicle returns for another inspection and again has too many "not ready" monitors, exceeding the acceptable limit. Another Not Ready Rejection VIRS will be issued. At this point a not ready waiver can be issued.
    4. Owner takes the two Not Ready Rejection VIRS to the local DMV office along with the manufacturers drive cycle, if one was used. If a Not Ready Waiver can be issued, DMV personnel will make the proper arrangements with the inspection station where vehicle will be inspected. Under the supervision of DMV the inspection station will proceed with the OBD inspection making special allowance to complete the emission inspection.
    5. The vehicle must pass the visual tamper and safety inspection portion of the emission inspection before a waiver number can be entered into the analyzer

Is my vehicle eligible for an exemption? [Back to Top]
 
DMV personnel may issue three types of exemptions:

  1. Kit Car/Custom Built Vehicle
  2. Out of I/M County
  3. One year
Contact your local DMV district office for more details (DMV District office locations ).