This is a mixed practice test pulled from across the ASE tests: engine repair, transmissions, drivetrain, suspension, brakes, electrical, A/C, engine performance, light diesel, and G1.
It's a good way to see where you stand before you pick which test to take first. Go through it without looking anything up and see which systems give you trouble.
-
Question 1 of 20
Technician A says adding equal shim thickness to both sides increases side bearing preload without changing backlash much. Technician B says side bearing preload can be set by tightening the bearing cap bolts past their specified torque. Who is correct?
Show answerHide answer
Answer: A. A only
Adding the same thickness to both sides squeezes the bearings harder without moving the ring gear toward or away from the pinion, so preload rises while backlash stays about the same. Technician A is right. Cap bolts are torqued to specification; preload comes from the shims or adjusters. Technician B is wrong.
-
Question 2 of 20
On this automatic climate control system, the HVAC module switches vacuum to the recirculation door actuator through an electric vacuum solenoid. The door never moves to recirculation. With recirculation commanded, 12.5 V is measured across the solenoid's terminals, and vacuum at its input reads 18 in. Hg. With the actuator's line disconnected and a gauge connected directly to the solenoid's output, it reads 0 in. Hg. What is the most likely cause?
Show answerHide answer
Answer: D. A failed vacuum solenoid
The solenoid receives its command voltage and its vacuum supply, but passes no vacuum from its own output when energized, so it has failed, either stuck closed or with an open coil. Voltage reaching it proves the command, not that it opened. The solenoid is replaced.
-
Question 3 of 20
After a minor rear-end collision, a car cranks but won't start. The fuel pump doesn't prime at key-on, and it has no voltage at its connector. The fuel pump inertia (crash) switch in the trunk is found tripped. What is the most likely cause?
Show answerHide answer
Answer: A. A tripped inertia switch
The inertia switch opens in an impact to shut off the fuel pump and reduce fire risk. Tripped, it leaves the pump without power. After checking for fuel leaks, the switch is reset.
-
Question 4 of 20
A light-duty diesel pickup with high-pressure common rail injection spent weeks idling for long periods with little load. Now it smokes heavily when first loaded, and a black, oily residue weeps from the exhaust joints. No codes are stored, and compression is good. What is the most likely cause?
Show answerHide answer
Answer: C. Wet stacking from idling
At light load, cylinder temperatures stay too low to burn fuel completely, so unburned fuel and soot build up in the exhaust: wet stacking. Driving under a good load usually clears it; extended idling is avoided.
-
Question 5 of 20
After an alternator was replaced, the battery runs down when the vehicle idles in traffic with the lights, blower and defroster on. The new alternator is rated at 90 A, while the vehicle is specified for 130 A. Its output test reaches its own 90 A rating. What is the most likely cause?
Show answerHide answer
Answer: D. An alternator with too low a rating
The replacement makes its full rated output, but that's only 90 A on a vehicle designed for 130 A. Under heavy loads at idle, demand exceeds what it can supply, so the battery makes up the difference and runs down. The specified alternator is installed.
-
Question 6 of 20
A truck with a recirculating-ball steering gear and parallelogram linkage has excessive free play at the steering wheel. All of these could cause it **EXCEPT**:
Show answerHide answer
Answer: D. Sector lash adjusted too tight
Free play comes from looseness anywhere between the steering wheel and the road wheels: the coupling, the gear's lash or the linkage joints. Sector lash adjusted too tight removes play; it makes the steering bind and return poorly, especially near center.
-
Question 7 of 20
Technician A says an aluminum cylinder head can be cleaned in a hot caustic tank, the same as a cast iron head. Technician B says an abrasive disc or wire wheel on a drill is the best way to clean aluminum gasket surfaces. Who is correct?
Show answerHide answer
Answer: D. Neither A nor B
Hot caustic solutions that clean cast iron dissolve aluminum, so Technician A is wrong. Abrasive discs and wire wheels can remove metal unevenly from the soft sealing surface and leave abrasive grit in oil passages, so many manufacturers prohibit them. Technician B is wrong too. Aluminum surfaces are cleaned with an approved scraper and solvent.
-
Question 8 of 20
Technician A says a clogged crankcase ventilation filter lowers crankcase pressure. Technician B says a crankcase pressure sensor reading is checked key on, engine off, against its specified at-rest value before a component is condemned. Who is correct?
Show answerHide answer
Answer: B. B only
Blow-by that can't pass a clogged filter builds pressure in the crankcase, pushing oil past seals. Technician A is wrong. With the engine stopped, a crankcase pressure sensor should read its specified at-rest value; a reading that's off shows a sensor or circuit fault before anything else is condemned. Technician B is right.
-
Question 9 of 20
Right after a clutch replacement, the clutch won't release and there's a scraping noise when the pedal is pressed. With the transmission removed, the disc's hub is found facing the flywheel, and the disc is stamped "flywheel side" on the face that's toward the pressure plate. What is required?
Show answerHide answer
Answer: A. Reinstall the disc correctly
Installed backward, the disc's offset hub can rub the flywheel or its bolts and won't move away cleanly, so the clutch can't release and scrapes. The disc is reinstalled with its marked side toward the flywheel, and the flywheel, hub and springs are checked for contact damage.
-
Question 10 of 20
At start-up, a combined low-pressure and malfunction TPMS telltale flashes for about a minute and then stays on. All four tires are at the correct pressure. What is the most likely cause?
Show answerHide answer
Answer: D. A TPMS system malfunction
On a combined telltale, flashing for about a minute and then staying on indicates a system malfunction, not low pressure. It may be a sensor that can't be read, such as one with a dead battery, or another system fault. A steady lamp without flashing indicates low pressure. The fault is diagnosed with a TPMS tool or scan tool.
-
Question 11 of 20
Technician A says the battery should be disconnected during programming to protect the module. Technician B says the engine should be running during programming to keep system voltage up. Who is correct?
Show answerHide answer
Answer: D. Neither A nor B
Programming needs steady power, so the battery stays connected with a maintainer holding voltage stable. Technician A is wrong. It's normally done key on, engine off, following the tool's prompts, and a running engine can interrupt it. Technician B is wrong too. A voltage dip or interruption can leave the module unable to start the engine.
-
Question 12 of 20
On an indirect-injection diesel head, prechamber (swirl chamber) protrusion relative to the deck is checked because a prechamber standing too far above the deck can:
Show answerHide answer
Answer: B. Hold the head gasket off its seal
Prechambers are pressed into the head, and their faces form part of the deck. One that stands too high keeps the gasket from clamping evenly around it, causing a combustion leak, and can come close to the piston. Protrusion is measured with a dial indicator, including after resurfacing, and corrected as service information directs.
-
Question 13 of 20
Technician A says that when the throttle is snapped open and released on a healthy engine, vacuum drops sharply and then rises briefly above the idle reading before settling. Technician B says a vacuum reading held at a steady 2,500 rpm is used mainly to check ignition timing. Who is correct?
Show answerHide answer
Answer: A. A only
Snapping the throttle open drops vacuum close to zero, and when it closes, vacuum overshoots above the idle reading before settling. A quick, good overshoot suggests the rings and valves are sealing well. Technician A is right. Holding a steady 2,500 rpm is mainly a test for exhaust restriction, which shows as vacuum slowly falling, so Technician B is wrong.
-
Question 14 of 20
A cable-shifted transaxle is hard to shift into every gear, whether the engine is running or off. With both cables disconnected at the transaxle, its shift levers move through every gear easily by hand. The shift cable is stiff when moved at its transaxle end. What is the most likely cause?
Show answerHide answer
Answer: C. A binding shift cable
Disconnecting the cables splits the system in two. The transaxle shifts freely by hand, and the stiffness stays with the cable, so the cable is binding. It's inspected for kinks, damaged housing or corrosion and replaced.
-
Question 15 of 20
During an alignment, caster is out of specification on the right side. The right strut rod's bushings are cracked and collapsed, and the rod moves in its frame mount. What should be done?
Show answerHide answer
Answer: B. Replace the bushings, then align
The strut rod locates the lower arm fore and aft, which sets caster. With collapsed bushings, the arm moves and caster changes. The bushings are replaced first, then caster is set.
-
Question 16 of 20
Technician A says a plugged transfer case or axle vent can push fluid out past seals. Technician B says vent hoses are routed up high so water isn't drawn in during water crossings. Who is correct?
Show answerHide answer
Answer: C. Both A and B
As a unit heats, the air in it expands; a plugged vent lets pressure build and forces fluid past seals. Technician A is right. When a hot unit is plunged into cold water it draws air in, so vent hoses are routed high to draw air rather than water. Technician B is right too.
-
Question 17 of 20
Technician A says tires are inflated to the maximum pressure molded on the sidewall. Technician B says tires are inflated to the vehicle placard pressure, cold. Who is correct?
Show answerHide answer
Answer: B. B only
The sidewall shows the tire's maximum pressure, not the vehicle's operating pressure. Technician A is wrong. The vehicle placard, usually on the driver's door jamb, gives the cold pressures for that vehicle's load and handling. Technician B is right.
-
Question 18 of 20
What is the main job of a shock absorber?
Show answerHide answer
Answer: C. To damp spring motion
Springs absorb bumps but keep bouncing on their own. The shock absorber converts that motion into heat so the body settles quickly and the tires stay on the road.
-
Question 19 of 20
An engine stalls occasionally after long drives and restarts once it cools. A crankshaft position sensor circuit code is stored. Its freeze frame shows coolant at 228°F and intake air at 130°F. The sensor checks good when cold. What should be done next?
Show answerHide answer
Answer: C. Heat-test the crank sensor
The freeze frame shows the code set with the engine fully heat-soaked, and the sensor tests good cold. Warming it with a heat gun while watching its signal on a scope or scan tool reproduces a heat-related dropout before anything is replaced.
-
Question 20 of 20
Since a front caliper was replaced, the brake pedal feels spongy and firms up when pumped. The fluid is full, the booster works normally, and there are no leaks. What is the most likely cause?
Show answerHide answer
Answer: B. Air in the hydraulic system
Fluid doesn't compress, but air does. Air let in when the caliper was replaced compresses as the pedal is pressed, so the pedal feels spongy; pumping temporarily packs it. The system is bled as service information directs.
Want more? ASE Pro has 2,100+ practice questions with explanations.
Look at which systems you missed, not just your score. That tells you which ASE test you're closest to passing and which one needs more work.
Ready to focus on one test? Try the A-series and G1 practice tests below.
Want more questions like these?
ASE Pro has 2,100+ practice questions with explanations, timed practice exams, and weak-area drills.