What Happens if You Fail a Breathalyzer During a Texas DWI Stop?

 Posted on September 12, 2025 in DWI

If you are pulled over in Texas and fail a breathalyzer test, you may face serious legal consequences right away. A failed test can trigger both administrative penalties and potential criminal charges. Texas law treats driving while intoxicated (DWI) as a serious offense, and even a first-time arrest can disrupt your life significantly. Working with an experienced Tarrant County, TX DWI defense lawyer is your best chance at fighting the charges against you.

Can You Get a False Positive on a Breathalyzer Test?

Breathalyzer devices are not perfect, and false positives happen more often than most people realize. The machine measures alcohol in your breath to estimate blood alcohol concentration (BAC). However, certain everyday factors can affect results, even if you are sober. Some things that could cause a false positive include:

• Acid reflux, GERD, or diabetes

• Certain medications

• Mouthwash or breath sprays that contain some alcohol

• Foods like ripe fruit or yeast products

• Fumes from paint, cleaners, or gasoline

• A poorly calibrated or mishandled device

If you are worried that taking the test was a mistake, just know that you did not have a choice. Under Texas Transportation Code § 724.011, drivers are considered to have given "implied consent" to submit to breath or blood testing if they are lawfully arrested for DWI. Refusing the test can result in license suspension, even though taking the test does not guarantee accuracy.

How Do You Challenge a DWI Charge With a Failed Breath Test in Texas?

Under Texas Penal Code § 49.04, a person commits DWI if they operate a vehicle in a public place while intoxicated. The law requires the prosecution to prove not just that you failed a test, but that you were actually intoxicated while driving.

An attorney may challenge whether the traffic stop itself was lawful. If the officer did not have reasonable suspicion to pull you over, any evidence gathered, including the breath test, may be excluded. Under Texas Code of Criminal Procedure Article 38.23, evidence obtained illegally cannot be used against you in court.

Your lawyer can also investigate whether the machine was properly maintained and whether the test was administered correctly. They will also investigate the circumstances leading up to your arrest to see if anything else could have caused a false positive breath test.

What Evidence Can You Use To Fight a DWI Charge?

Useful evidence for challenging a DWI charge may include:

• Calibration and maintenance records showing that the breathalyzer was not working properly.

• Police body cam or dash cam footage that reveals mistakes during the stop or test.

• Medical records demonstrating conditions that affect results.

• Witness testimony that you did not appear intoxicated.

In some cases, an independent expert may review the breathalyzer data and provide testimony on its reliability. Courts must consider all evidence, not just the breath test, when determining guilt.

Call Today To Speak with a Dallas, TX DWI Defense Attorney

If you are facing DWI charges, speak with a Tarrant County, TX DWI defense lawyer who will fight to protect your rights. At Law Office of Michelle Poblenz, we bring more than 25 years of legal experience to every case. Attorney Michelle Poblenz is a former prosecutor for the Dallas County District Attorney’s Office, and her background gives her unique insight into how prosecutors build DWI cases and how to identify weaknesses in them. 

She has been recognized for her professional achievements, holding distinctions such as Lead Counsel Verified and being named one of the Best Criminal Defense Attorneys in Irving (2023) by Expertise.com. In addition, Michelle Poblenz speaks Spanish, allowing her to serve a broader range of clients with compassion and understanding. If you need legal representation, call us at 469-845-3031 so we can get started on your case.