Why an IID False Positive Causes Concern
An ignition interlock device records breath tests. An IID false positive is a reading that shows alcohol when the driver believes none was consumed. Since installers report certain events to the DMV, a disputed reading deserves prompt attention.
So it helps to understand what the law says the device and installer track. It also helps to keep records right away.
How the Device Logs Tests
Vehicle Code section 23575.3 defines a random retest as a breath test the driver performs at random intervals after startup while the engine runs. It defines a bypass as failing to take a retest or failing one above 0.03 percent. So the device tracks more than the first test.
The installer must also notify the DMV of removal, tampering or three or more maintenance failures. Therefore, device records can reach the department.
Products That Contain Alcohol
The California Driver Handbook says alcohol in any form counts, and it names medications like cough syrup. So a product with alcohol can matter for an interlock reading as well. Read each label before use.
Also ask the installer and the product’s pharmacist about alcohol content when a label is unclear.
Steps After an IID False Positive
Retest when the device allows. Then write down the time, what was eaten or used and any symptoms. Also keep receipts and labels for products used before the test.
Next, contact the installer and ask for the log. If the reading leads to a notice, talk with a lawyer before responding.
How Records Can Help
Written notes made at the time help a lawyer review the event. For instance, the log may show later passing retests, and receipts may show what was used. Keep copies of everything.
The DMV DUI page explains interlock and restriction options after a DUI. The article on IID installation California steps explains service rules, and the guide on California DUI IID requirements covers the term.
Why an IID False Positive Can Extend the Term
Section 23575.3 says periods of noncompliance do not count toward the required term. So an unresolved IID false positive can push the end date later. In addition, ask the installer how long the device keeps logs, since that answer affects how long records stay available.
Save notes, receipts and installer letters for each disputed test in one folder. That file makes any later review easier.