ASE G1 Auto Maintenance and Light Repair Certification Test Study Guide

The National Institute for Automotive Service Excellence allows 90 minutes to complete the G1 exam, which includes both the questions used for scoring and additional unscored, or pre-test, questions mixed into the same time limit.

The G1 exam includes 55 total questions, but only 45 of those are scored; the remaining questions are unscored, pre-test items ASE uses to evaluate them for future exam forms.

ASE charges a $34 registration fee per order plus a $62 test fee for the G1 exam itself, so a candidate should budget for both charges when scheduling the exam.

ASE's G1 recertification exam uses 28 questions and allows 45 minutes to complete them, a shorter format than the initial certification test for technicians renewing their credential.

An ASE certification, including G1, stays valid for five years from the date it is earned, after which the technician must pass the shorter recertification exam to keep the credential current.

The G1 task list is organized into seven content areas, and Suspension and Steering carries the most questions of any single area, with 13 questions on the exam.

Brakes is the second-largest content area on the G1 task list, contributing 11 of the exam's questions, behind only Suspension and Steering in overall weight.

Engine Systems contributes 9 of the questions on the G1 exam, making it the third-largest of the test's seven content areas behind Suspension and Steering and Brakes.

ASE generally requires 1, 2, or 3 years of relevant hands-on work experience before a technician is eligible to test, with the exact requirement varying by the specific test and the technician's role or training background.

Automatic Transmission/Transaxle and Heating, Ventilation, and Air Conditioning are the two smallest content areas on the G1 task list, each contributing 4 questions to the exam.

A micrometer gives an accurate rotor thickness reading in thousandths of an inch, which the technician then compares to the minimum, or discard, thickness stamped or cast into the rotor to decide whether it can be resurfaced or must be replaced.

The lift arms or jack must be placed under the vehicle manufacturer's specified lifting points, usually reinforced areas of the frame or pinch welds, since lifting at an unsupported point can bend body panels or cause the vehicle to fall.

Lug nuts should be tightened in a star, or crisscross, pattern in stages up to the final torque value, which seats the wheel evenly against the hub instead of pulling it on at an angle.

A torque wrench applies the exact clamping force specified by the manufacturer, while an impact wrench used for final tightening can easily overtighten fasteners unevenly, which risks stretching studs, warping the rotor, or leaving the wheel improperly seated.

The technician should disconnect the battery and, on many systems, wait the manufacturer-specified period for the backup capacitor to discharge before disconnecting or working near airbag wiring, connectors, or modules, since these components can deploy unexpectedly if handled while energized.

A technician should follow the manufacturer's procedure for disabling the high-voltage system and use insulated tools and rated protective equipment, never assuming the orange high-voltage cabling is safe to touch without confirming the system has been properly shut down.

The technician should look for cracking, fraying edges, glazing, or missing chunks of rib material on the belt, since any of these conditions signal the belt has deteriorated and is at risk of slipping or failing.

An oily film running down a strut or shock body indicates the internal seal has failed and hydraulic fluid is leaking out, which reduces the unit's ability to control spring and body motion and is a standard reason to replace it.

A new strut and a worn strut damp spring motion differently, and mismatched damping from side to side can create uneven handling and uneven tire wear, which is why replacing both struts on an axle together is the accepted practice.

Tire pressure should be checked while the tires are cold, before the vehicle has been driven or after it has sat for several hours, since driving warms the air inside the tire and raises the pressure above the cold specification.

Many tire-pressure monitoring systems link each sensor's identification code to a specific wheel position, so after a rotation the system needs a relearn procedure to recognize which sensor is now in which position, or the warning light can stay on even with correct pressures.

A tire is considered worn to its legal minimum once the tread has worn flush with the built-in wear-bar indicators molded into the tread grooves, a point a tread depth gauge can also confirm directly.

The technician should confirm the noise changes with road speed and shifts in volume when the steering wheel is turned slightly to load the bearing differently, since these two patterns are what distinguish bearing noise from tire or drivetrain noise.

Underinflated tires tend to sag so that more of the load rides on the outer edges of the tread, producing faster wear at both edges of the tire while the center of the tread wears more slowly.

Overinflated tires bow outward in the middle of the contact patch, so more of the load and wear concentrates in the center of the tread while both edges wear more slowly in comparison.

A feathered wear pattern, where each tread rib feels sharp on one edge and rounded on the other when run across by hand, is the classic sign of a toe misalignment rather than an inflation issue.

Brake fluid can be checked visually for dark discoloration and tested with an electronic fluid tester that measures moisture content, since glycol-based fluid absorbs moisture over time, which lowers its boiling point and increases the risk of fade.

DOT 5 is a silicone-based fluid while DOT 3 and DOT 4 are glycol-based, and mixing these chemically different fluid families can cause seal damage, fluid aeration, and reduced braking performance, so the two families should never be combined.

A spongy pedal that sinks farther than normal before firm resistance usually points to air trapped in the hydraulic lines, since air compresses under pressure while brake fluid does not, and bleeding the system is the correct repair.

Clean, properly lubricated slide pins let the caliper float freely and center itself over the rotor, so both pads wear evenly; dirty or dry slide pins can bind and cause one pad to wear faster than the other.

A shoe contaminated with brake fluid should be replaced, since fluid soaks into the friction lining and changes its friction characteristics in a way that wiping the surface clean cannot fully correct.

With the vehicle on level ground and the engine off long enough for oil to drain back to the pan, the dipstick should be pulled, wiped clean, fully reinserted, then pulled again to give an accurate reading.

Holding the filter up to a light source shows how much dirt has built up across the media and reveals tears or damaged pleats, both of which mean the filter should be replaced rather than reused.

A burnt smell combined with metal particles suggests internal wear or overheating inside the differential's gears or bearings, and this finding calls for further inspection rather than simply topping off the existing fluid.

Because a torn boot lets dirt and moisture into the joint, the technician should inspect the CV joint itself for contamination and wear in addition to replacing the boot, rather than only addressing the tear.

Grease should be added through each fitting until fresh grease is seen purging from all of the joint's seals, which confirms the grease reached the internal needle bearings and pushed out old, contaminated grease.

Fluid that has darkened and developed a burnt odor has likely been exposed to excessive heat or has broken down chemically, reducing its ability to lubricate and allow smooth clutch application, which calls for further inspection.

Before condemning the compressor, the technician should check whether a low-pressure safety switch has opened because of a low refrigerant charge, since many systems prevent the clutch from engaging under that condition to protect the compressor.

Condensation produced as the evaporator cools the air is meant to drain outside through a dedicated tube, and a clogged drain lets that water back up and pool inside the cabin, where standing moisture also produces a musty smell.

R-134a and R-1234yf use different service fittings specifically to prevent the two refrigerants from being cross-contaminated, so the technician must check the underhood label identifying the system's refrigerant type before connecting any equipment.