What Happens If You Fail an Ignition Interlock Test?

You probably weren’t thrilled about having an ignition interlock device (IID) installed in your car. But at least you could maintain your freedom. You just had to play by the rules — which you did. So why is your IID reporting that it detects alcohol? Or maybe you had a drink but expected to be well below the limit. Whatever the circumstances, an IID test that detects alcohol can be a scary thing.

In this article, we explore some of the common implications of a failed ignition interlock test. We’ll also discuss some of the legal principles behind challenging these test results. State law generally governs in this area, so the specifics can vary by jurisdiction.

If you’re not quite sure about your next steps after a failed IID test, consider speaking with an attorney licensed in your state. Many specialize in matters related to driving under the influence (DUI) or driving while intoxicated/impaired (DWI) charges. A DWI/DUI attorney can help you understand your options at this uncertain time.

What Is an Ignition Interlock Device?

An IID is a small machine installed in a vehicle to help prevent drunk driving. It works like a breathalyzer. Before starting the car, the driver must blow into the device. If it detects alcohol above a certain breath alcohol concentration (BrAC) limit (usually around 0.02%), the car won’t start. This is much lower than most states’ legal limit for blood alcohol concentration (BAC) of 0.08%.

If the driver’s breath sample shows a BrAC below the preset limit, the device will allow them to start the vehicle. IIDs can also conduct random rolling retests while a car is running to make sure the driver is still sober.

When Are IIDs Used?

Ignition interlock devices are often court-ordered for people who have been convicted of DUI/DWI offenses. Some states’ departments of motor vehicles (DMVs) can require an IID even if the court doesn’t.

For example, a DMV may impose an ignition interlock device requirement after a DUI/DWI conviction or administrative license suspension.

What Happens If an IID Detects Alcohol?

If an IID detects alcohol on your breath that’s over the preset limit, it will:

• Prevent the vehicle from starting (lockout)
• Record the result as a failed test
• Report the failure to the monitoring agency

Drivers can often retest after a short amount of time. If their BrAC drops below the limit after the lockout period, the car will start. But each failed breath test is still logged and may count as an ignition interlock violation, depending on state regulations.

If an IID detects alcohol on a random retest while a person is driving, the vehicle won’t shut off for safety reasons. But the driver might be forced to pull over because the device may trigger alarms like flashing lights or honking for alert purposes.

What Agencies Monitor IIDs?

A combination of state and local government agencies, as well as court systems and probation departments, monitor ignition interlock device programs. Some use real-time reporting, while others review data during calibration appointments, typically scheduled every 30–120 days.

Depending on state law and the DWI/DUI offender’s sentence, IIDs could be monitored by:

• DMVs: Often oversee IID programs and receive data to ensure drivers are complying with the terms of their restricted licenses
• Courts: Usually receive regular driver compliance reports on court-ordered IIDs, including test failures, missed appointments, and tampering attempts
• Probation Officers: Typically get IID data for their assigned people on probation for DWI/DUI offenses

In some cases, treatment providers may also receive IID data if treatment is part of the offender’s rehabilitation plan.

What Are the Consequences of a Failed Ignition Interlock Test?

In most cases, the agency or a compliance team reviews the IID violation to determine if it was a first-time issue or part of a pattern.

Depending on the state and the number of IID violations, consequences may include:

• Temporary lockout: A short period of time before you can retest
• Extended IID requirement: Longer time in the respective IID program
• Permanent lockout: Often requiring a service center visit for reinstatement
• Driver’s license suspension/revocation: Loss of driving privileges for repeat or serious violations

If the IID is part of a legal sentence, violations may trigger a hearing or additional penalties. In some cases, courts may impose jail time for willful non-compliance, patterns, or violation of probation terms.

Can An IID Be Wrong?

Yes. IIDs can register what seem like false positives. But these are usually due to alcohol-containing substances in the mouth, not actual alcohol in the bloodstream.

IIDs use alcohol-specific fuel cell sensors that are generally accurate, but they can’t tell the difference between alcohol from a drink and alcohol from other sources, like mouthwash, breath spray, cough syrup, or even foods like vanilla extract or ripe fruit.

These substances can leave residual alcohol in your mouth, which may trigger a positive IID reading even if you haven’t been drinking. Health conditions like acid reflux or diabetes can also sometimes cause a false reading due to substances like acetone in the breath.

If an initial test detects alcohol but you haven’t been drinking, you may want to retest after the lockout period. However, your device will still log and report the failed test(s), so you may also want to take action.

What Can I Do?

Document everything. Record what you ate, drank, or used (like mouthwash) before the test. If possible, go to a clinic or hospital that offers blood alcohol content or urine alcohol tests. Substances that cause false positives on IIDs don’t typically affect blood or urine alcohol tests in the same way.

Evidence from these tests can help you challenge the false positive and potentially get it removed from your record.

How Do I Challenge or Appeal a Failed IID Test?

The specific processes depend on state law and the terms of your IID program. Still, you’ll likely have several options. These might include:

Formal Hearing

You may be able to request a hearing with the court or the monitoring agency that oversees your IID program. At the hearing, you’ll typically ask for leniency or a review of the violation. You’ll also want to present evidence that the test result was inaccurate and explain any factors that may have caused the false positive.

Appeal

If the failed test leads to penalties like license suspension or program extension, you may be able to appeal the decision. 

An appeal usually involves:

• Filing paperwork with a higher court or administrative board
• Arguing that there was a legal or procedural error
• Providing documentation or expert testimony about the device’s accuracy

If successful, you may get the violation dismissed and your IID requirements adjusted accordingly.

IID Modification

If you can’t get the violation overturned, you might still be able to request a modification to your IID program. This could reduce the duration of the requirement or limit when the device must be used, especially if you’ve been compliant.

Getting Legal Guidance

Legal support can be critical as you move forward, especially if the failed test might affect your probation, license, or employment. Consider speaking with a DUI/DWI attorney licensed in your state. You can share the specifics of your situation with them confidentially. They can help you understand your various options under the circumstances.

FindLaw’s free directory of DUI/DWI attorneys can connect you with experienced advisors in your area. To view ratings and other information for local experts, click on your state, then city. You can also check which ones offer free consultations.

The stakes can often be high with a failed IID test. Give yourself the peace of mind that comes with informed decision-making. Enlist the help of a trusted advocate.