Michigan SOS mechanic test

Breath Alcohol Ignition Interlock Device (BAIID)

Breath Alcohol Ignition Interlock Device (BAIID) is one of the 20 Secretary of State mechanic certification tests. Here's what the test covers, according to the state's published outline.

Topic guide · questions soon

What's on the test

Official topicWeight
Ohm’s law and electrical symbol recognition
  • Ohm’s Law
  • Splice symbol
  • Diode symbol
  • Relay symbol
13%
Starting system diagnosis
  • Starter current draw
  • Starter relay diagnosis
  • Circuit resistance Test
  • Battery test
13%
Miscellaneous circuit diagnosis
  • Regulator diagnosis
  • Horn circuit diagnosis
6%
General
  • Electrostatic discharge
  • Voltage drop test
  • Circuit protection
13%
Test meter usage
  • Ohmmeter usage
  • Voltmeter usage
6%
Legal requirements
  • Installer requirements
  • Service area requirements
  • Customer requirements
  • Customer training
25%
General
  • Violation reset
  • Tampering
  • Emergency bypass code
  • Removal of device
  • Set point
24%

Source: SOS Mechanic Testing Categories Overview (PDF). Test format: most SOS mechanic tests have 55 questions, and a few have 65–100 (SOS FAQ). Passing scores vary by test; your result letter shows the passing score and your score.

Practice questions coming soon

The Breath Alcohol Ignition Interlock Device (BAIID) practice bank is being written to the official outline below. The All-Mechanic pass will include it when it launches.

Banks available now: Engine Repair · Front End, Suspension & Steering · Brakes & Braking Systems · Electrical Systems · Engine Tune-Up & Performance

Test-day facts

Source: michigan.gov/sos mechanic testing

Breath Alcohol Ignition Interlock Device (BAIID) test FAQ

How many questions are on the Michigan Breath Alcohol Ignition Interlock Device (BAIID) test?

The Secretary of State says most mechanic tests have 55 questions and a few have 65 to 100. The test is “quick pass,” so it ends as soon as you reach the minimum passing score.

What topics are on the Breath Alcohol Ignition Interlock Device (BAIID) test?

The SOS Mechanic Testing Categories Overview lists: Ohm’s law and electrical symbol recognition (13%), Starting system diagnosis (13%), Miscellaneous circuit diagnosis (6%), General (13%), Test meter usage (6%), Legal requirements (25%), General (24%).

How much does the test cost, and where do I take it?

Each mechanic test costs $18 (effective July 1, 2026). Tests are taken on a touch-screen kiosk at any Secretary of State office; pre-register and schedule through SOS Online Services. Approved automotive schools can also test their students.

Are these the real test questions?

No. MI Trade Prep questions are original practice items written to the official topic outline. They are not actual exam questions, and MI Trade Prep is not affiliated with the Michigan Department of State.

Sources: SOS mechanic testing · SOS mechanics page · SOS mechanic FAQ