An in-vehicle interlock is an alcohol interlock device that controls engine starting based on the result of the driver's breath test. A first-time user may start testing as soon as the handset screen turns on, or may think the vehicle itself is broken when the engine does not start. However, an interlock is a device in which test preparation, breath sampling, result judgment, and engine start control follow one another, so the first task is to know what to look for at each stage.
For example, the DATECH AF-i1 consists of a handset that the driver blows into and a control box that handles signals on the vehicle side. The handset shows test guidance and results, and the control box controls engine starting based on that result. On first use, rather than memorizing specific screen messages or button positions, it is less confusing to walk through the flow once, from the ready state to checking the result, using the user manual for the installed device.
Check that both the vehicle and the device are ready
First, park the vehicle safely and set it up as you normally would before starting, including gear position and parking brake. Next, check that the handset belongs to the device installed in that vehicle and that there are no visible problems with the connecting cable or how it is mounted. The handset and control box have different roles, so do not assume test preparation is finished just because you are holding the handset.
After the power comes on, wait until the screen or indicator light shows that the device is ready to test. On the AF-i1, warm-up time can vary with temperature, previous test results, and other factors, and the wait can be longer especially at low temperatures. If you blow before it is ready or try to start the engine repeatedly, it becomes hard to tell what is causing the problem. Your first step is to read what action the screen is asking for next.
Take the test yourself, following the on-screen guidance
When the ready prompt appears, use the mouthpiece and provide your breath as described in the device manual. This is not a step that someone else can do for you. The AF-i1 is described as having a function that detects whether a person is testing directly, based on the temperature, humidity, speed, and strength of the breath. Trying to solve a problem by switching who takes the test is therefore not appropriate.
At first, when to start blowing or how to keep it up may feel unfamiliar. Rather than repeating attempts at will, check whether the screen means failure, retry, or wait. Guidance and required actions can differ by device, so follow the manual for the installed model and the training you received at installation for the exact breathing method.
| Stage to check | What to look at on the screen or device | Next action |
|---|---|---|
| Before testing | Whether the ready prompt has appeared | Wait until it is ready |
| During testing | Breathing method or retry guidance | Take the test yourself as instructed for that model |
| After testing | Result showing start approval, wait, or inspection | Try to start the engine or request support, depending on the result |
Read the result as approval, wait, or inspection request
After the test, first check whether the result is a start approval. Move on to the vehicle's normal starting procedure only when you have confirmed the approval indication. An interlock approval means the device permits engine starting based on that test result. It is not an indication that judges the vehicle's other maintenance conditions or the overall safety of driving.
If a retest or wait prompt appears, first follow the conditions requested on that screen. On the other hand, if the indication is an error or calls for inspection, note what is shown and when it occurred, and get ready to pass it on to the installation or management support contact. The AF-i1 is described as storing interlock usage data, including test results, vehicle ACC, engine starts, and events related to tampering, and allowing it to be managed and downloaded with dedicated software. So rather than vaguely saying "the engine won't start," passing on the actual indication and what you did just before it helps identify the cause.
Learn the sequence through a hypothetical first day
As a hypothetical example, suppose that on a winter morning a driver tries to test as soon as the handset powers on and gets a retry or wait prompt. The facts to observe are whether "the power is on" and "the device is ready to test" are the same state, and whether the screen is asking for an immediate retest or a wait of some time. At low temperatures, the device's warm-up time can differ from usual, so you cannot conclude from this situation alone that the device is faulty or the test result is abnormal.
One possible action is to wait until the device is ready if the screen shows a wait prompt, and, if it shows a retry prompt, to test again yourself following the breathing procedure in the manual. The completion standard is not how many times you pressed the start button. It is having confirmed the ready prompt, finished the test, and identified whether the state is approval or one that needs support. If the error continues, leave the vehicle and report the indication, the time, and the vehicle's location to the installer or the support contact set in advance. If you must leave, consider other transport arranged beforehand.
Set up the support route before first use
On the first day, do not practice only normal tests. Also decide who to tell, and what information to give, when the result is not an approval or an inspection prompt appears. A fleet manager can consider an operating rule that keeps the device model name, the support contact, and an example of the information to pass on somewhere easy to find in the vehicle. The information to pass on should be checkable facts, such as the message on the handset, the test time, and when the engine start was attempted, rather than the driver's vague memory.
The possibility that an inspection or calibration reminder may appear is also worth including in first-use training. Official AF-i1 information lists an inspection and calibration reminder function, and usage data is also stored. If you classify the reminder as a signal to check the device's condition rather than as an annoyance to switch off, the driver can move on to the needed support procedure instead of repeatedly making ad hoc adjustments on the spot.
First use is not complete the moment the engine starts once. You can say you understand the pre-start test sequence only when you wait for the ready signal, take the test yourself as instructed, and choose a different next action depending on whether the state is approval, wait, or inspection.
