What Happens If Your Ignition Interlock Test Fails?

Girl sleeps in a carIgnition interlock devices (IIDs) are rapidly becoming a standard consequence for those convicted of alcohol-related driving offenses. Almost half of the states in the U.S. now have mandatory installation laws for anyone convicted of driving with a blood alcohol concentration (BAC) at the national legal limit of .08, proving that these devices are a solution to prevent drunk driving incidents from occurring. As an IID is technology-based, it stands to reason that at times, the devices can incorrectly detect the presence of alcohol in the breath and blood of the driver. If this happens, keep in mind that it is in your best interest to continue providing a breath sample that proves you are “clean,” so that the false positive result can be explained.

Ignition interlock devices detect the presence of alcohol in the blood stream through a breath test. The alcohol-specific fuel cell technology is highly refined to eliminate the chance of a false positive test that would indicate a driver has been drinking, when he or she has remained sober. In fact, the most common reason that an ignition interlock test fails is because the driver has consumed alcohol. If you have been drinking and your IID detects alcohol in your ignition interlock test, it will be reported to the agency in charge of monitoring your device.

Regardless, If your ignition interlock test fails, you will be given the opportunity to test again after a few minutes. This is to allow any other substances (like alcohol-based mouthwashes) to dissipate from your mouth, or, to give you the chance to consider if you have been consuming alcoholic beverages. After a subsequent test failure, you will be given more time before you can test again. Once your breath test is “clean,” you should be able to operate your vehicle normally.

In the event that your ignition interlock test fails because the IID is broken or needs to be serviced, it is your obligation to have any maintenance or repair done. Be sure to always keep the name and number of your ignition interlock service provider handy to avoid any delays in getting yourself back behind the wheel.


  1. I had a false positive of .04, not sure why exactly and a little over a minute later it was a .01 and I was able to start my car. A month later I am served a subpoena To Show Cause as to why i shouldn’t have my diversion taken away and be charged with DUII because of the, what I thought, was obviously a false positive blow. I’m sure the third blow after as I was driving to work was a. 0.0 WTH?

    • Thank you for your question. As we cannot provide legal advice, we suggest you speak with your attorney about your options in this situation.

      • Seriously? Seems like if your pie ID is that sense that I have and sensitive enough to record false positive as to the specific foods, that possibly your organize a shad might be able to support somebody who is being falsely accused of a positive below when it was a false positive. Have you looked into what it cost to hire an attorney he’s days? On top of the fact that I got my DUII 2 1/2 hours from my home. Because your device is overly sensitive at times, I’m going to have to spend several hundreds maybe thousands of dollars to try to get out of a conviction. Not to mention that it is a piece of junk that malfunctioned constantly and I had to get a reset several times. Seems like since you guys know that it is this way that you would be more supportive of the people that have to rent them from you. Where is the justice?

        • We apologize if you thought we were being unhelpful. The device detects any trace of alcohol in your breath, and this includes the alcohol in mouthwash and some types of food. The only suggestion we can give you is to respond to the subpoena with the possible reason why you blew a .04 and then a .01 a minute after. It may have been your mouthwash or something you ate. You may also request a report from your provider that shows the time the .04 and .01 BAC were recorded that you can provide when you respond to the subpoena.

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