G1 Auto Maintenance & Light Repair — practice test

High-yield G1 topics

The material that shows up year after year. If you're short on time, start here.

• Rotor measurement and pedal pulsation. The number cast or stamped on the rotor is the DISCARD/minimum thickness. Know how to mic a rotor in at least four spots, and know the two specs that actually cause a pulsating pedal: lateral runout (typically about 0.002 in max at the friction surface) and thickness variation/DTV, where as little as 0.0005 in telegraphs to the pedal. Expect a question where the fix is an on-car lathe or correcting hub runout, not just slapping pads on.
• Tire wear patterns tied to a specific alignment angle. Toe wear is feathered/sawtooth across the tread. Camber wear is one shoulder only, smooth. Cupping or scalloping points at worn shocks and struts, or a bent/out-of-balance assembly. Center wear is overinflation, both shoulders is underinflation. Caster is a directional-stability and pull angle - it does not wear tires. That distinction shows up on nearly every form of the test.
• Battery and charging by the numbers. Load test at half the CCA rating for 15 seconds, minimum 9.6 V at 70 F, or conductance test as the modern equivalent. Charging voltage in the 13.5 to 14.7 V range depending on temperature. Parasitic draw in the 25 to 50 mA neighborhood after the modules time out and go to sleep - and you have to wait for that timeout before you condemn anything. Know AGM versus flooded charging, and why start-stop vehicles need a battery registration or BMS reset.
• Voltage drop testing. This is the single most tested electrical concept at MLR level. Circuit loaded and energized, meter in parallel across the connection or load, and a good ground or feed side should total well under about 0.5 V (roughly 0.1 V per connection). An unloaded resistance check can read 0.2 ohms and look perfect while that same cable is toast under 200 amps of crank.
• Fluid identification and compatibility. Brake fluid: DOT 3, 4, and 5.1 are glycol-based and hygroscopic; DOT 5 is silicone and does not belong in an ABS system or any system that ever saw glycol. Gear oil: GL-5 in a manual transmission with brass synchros attacks the yellow metal, and ATF is never universal. Coolant: OAT, HOAT, and IAT are not interchangeable and mixing them gels the system. Engine oil: API SP / ILSAC GF-6 exists largely because of LSPI in turbo GDI engines, which is why viscosity substitution is not your call.
• Refrigerant and HVAC service. R-1234yf and R-134a use different service fittings for a reason. Identify the refrigerant before you touch a system, then recover - cross-charging or topping off a contaminated system is a hard no. HVAC questions here stay service-level: cabin filter, evaporator drain, condenser airflow, and what the low-side and high-side gauges do on a normal system.

Where techs lose points on G1

Good technicians miss these — not from lack of skill, but because the question is built to catch them.

• Machine-to versus discard thickness. The spec on the rotor is where it goes in the scrap bin, not where you can cut it to. A rotor that measures right at minimum after machining is a failed part. The answer that says 'it is still at spec, machine it and reinstall' is the bait.
• Ohms instead of volts. Every look-alike electrical answer offers a resistance test on a suspect cable or ground. Resistance testing an unloaded circuit is the classic wrong-but-reasonable choice. If the circuit carries current, the correct answer is a voltage drop test under load.
• Tech A / Tech B absolutes. When one tech's statement contains 'always,' 'never,' or 'all vehicles,' that tech is usually wrong - especially on TPMS relearn procedures, ATF service intervals, and lug torque. On that last one: a torque stick is a torque-limiting approximation, not a torque wrench, and the right answer is almost always final torque by hand, in a star pattern, to spec.
• Over-diagnosing. G1 is maintenance and light repair. When a question describes a symptom that needs a scan tool, a Mode $06 pull, or pressure and volume testing beyond MLR scope, the correct answer is frequently to inspect, verify the basics, consult service information, and refer it - not the deep diagnostic path that feels more impressive.

A study plan that works for G1

Roughly two weeks of real preparation, in the order that actually builds on itself.

1. Days 1-5: Brakes and suspension/steering. This is half the test, so it gets half the time. Drill the measurement specs cold - rotor discard, lateral runout, DTV, lining thickness, wheel bearing play with a dial indicator, ball joint loaded versus unloaded checks. Then work the tire wear chart until you can name the angle from the pattern without thinking about it.
2. Days 6-8: Engine systems plus the fluid matrix. Belts (EPDM wear is measured with a gauge, not judged by cracks), cooling system pressure testing and coolant chemistry, oil specs and why they are not substitutable, filters, spark plug gap and torque. Build one page listing every fluid on a vehicle and what happens when you put the wrong one in.
3. Days 9-11: Electrical, HVAC, and drivetrain. Electrical carries real weight and voltage drop testing alone is worth an evening. HVAC, automatic transmission, and manual drive train are only a few questions each - do not sink days into them. Be solid on refrigerant handling, ATF level and type procedure, clutch free play, U-joints, and GL-4 versus GL-5, and move on.
4. Days 12-14: Timed practice only. Full-length sets under the clock, then review every miss out loud and say why the distractor was attractive. If you cannot explain why the wrong answer looked right, you have not learned it yet. Any area still under about 75 percent gets one focused pass the night before.

Sample G1 questions

Straight from the bank — answers highlighted, with the explanation underneath.