What Happens if You Fail an Ignition Interlock Test in Texas?

 Posted on September 23, 2026 in DWI

A failed ignition interlock test in Texas gets recorded by the device and reported to whoever is monitoring you. That may be the court that set your bond, your probation officer, or the Texas Department of Public Safety. What happens next depends on why the device was installed and what the full report shows.

One failed reading does not necessarily mean jail time, but it does start a review. If you got a DWI ignition interlock violation notice in 2026, a Weatherford DWI defense lawyer can help you explain what happens next.

What Counts as a Failed Ignition Interlock Test?

An ignition interlock device flags all of the following:

• A startup test that reads above the set limit, which locks the vehicle out

• A rolling retest that reads high while you are driving

• A skipped or refused rolling retest

• Disconnecting the device, the battery, or the power source

• Missing a scheduled calibration or service appointment

• Any sign the device was bypassed or someone else blew into it

A very small amount of alcohol, from any source, can trigger a failure.

Who Finds Out if You Fail an Interlock Test in Texas?

An ignition interlock device stores every event with a date and time. Some models also take a photo at each test. The provider pulls that data at each service visit, usually every 30 to 60 days, and many devices report certain events right away.

Where the report goes depends on why the device is on your car. If a judge ordered it as a condition of bond under Texas Code of Criminal Procedure Article 17.441, a violation of the court order must be reported to the court. If you are on community supervision, the violation is also reported to your supervising officer. DPS can request interlock records, but it does not automatically receive every failed-test report.

Can You Go to Jail for Failing an Interlock Test?

If the device is a bond condition, the state can ask the judge to raise your bond, add conditions, or revoke the bond and have you rearrested while the case is pending.

If you are on community supervision, the prosecutor can file a motion to revoke, or a motion to adjudicate if you are on deferred adjudication. Texas Code of Criminal Procedure Article 42A.751 governs those hearings, and the judge does not have to revoke. They can continue you on supervision with changes instead. If the judge does revoke a deferred adjudication, the case is no longer deferred. You can be sentenced anywhere within the full range for the original charge.

Can You Get a False Positive on an Ignition Interlock Device?

An ignition interlock device measures alcohol, but it can’t tell where the alcohol came from. Common triggers include mouthwash, breath spray, some cough medicines, and other products that contain alcohol. Acid reflux can also push alcohol vapor up from the stomach.

Most of these leave a very different signature than drinking, and mouth alcohol clears fast. If you rinse with water, wait 15 to 20 minutes, and blow clean, that clean test lands in the same log right next to the failed one. A very low test result followed immediately by a clean test can be strong evidence that you were never intoxicated. 

What Should You Do After a Failed Interlock Test?

Do not ignore the notice, and do not explain it to your supervision officer before talking to your attorney. Write down everything you ate, drank, or took in the hour before the test, while you still remember. Keep receipts, pharmacy labels, and medical records that support it. If you can get an independent breath or blood test the same day, do that as well.

Ask for the complete device log, not just the violation summary the State sends over. The full log shows retests, timing, photos, and calibration history, and it often tells a different story than a single flagged reading.

Schedule a Free Consultation With Our Parker County, TX DWI Defense Attorney

Attorney Soraya Joslin has almost 30 years of experience. She served as an assistant district attorney for several years, so she knows how these reports and cases are handled. She can often address a violation with the court early, before it becomes a motion to revoke.

Contact Soraya Joslin, P.C. at 817-599-7005 to speak with our Weatherford, TX criminal defense lawyer.