The process is simple. If you pass, you are allowed to drive. If you fail, you’ll have to wait an hour to try again. Further, if a car thief does not have the Check Module – or know how to use it, the thief cannot start the car.
Press the "CHECK" button to start the impairment test.
Follow the flashing lights. The "CHECK" button activates the colored light-emitting diodes (LEDs) to rapidly flash in a fully random fashion – say: red, blue, green, red and blue. The user reacts to the rapidly-changing light pattern by pressing the buttons immediately adjacent to the light sources – it only takes about 2½ seconds.
If the test is passed, the engine can be started.
If the person checking their respective level of eye-hand coordination responds accurately and rapidly enough, the "OK" LED will flash and the tone generator will beep a "positive" performance. Under this circumstance, the driver has 10 seconds to use the key to start the automobile's engine. On the other hand, if the Check Module detects that the operator has not responded appropriately, the engine Immobilizer will not permit the starter to function.
Since "honest fumbles" will occasionally occur even when unimpaired, the SafeKey ignition interlock device will allow several opportunities to retry the test. If, however, after the third opportunity the test is not passed, the "CHECK" cannot be retried for an hour in order to allow the user an opportunity to gain further driving competence.