ASE practice tests, every option explained

Correct: A bigger alternator pulley slows the alternator at engine idle, so it cannot keep up with the lights until rpm rises.

Incorrect: An open diode cuts output at every speed, not only at idle.

Incorrect: A failed regulator would act up at every speed, not only at idle.

Incorrect: High ground resistance lowers output at every speed, not only at idle.

Correct: A cycling switch stuck closed keeps the compressor running so the evaporator freezes; ice blocks airflow and frost forms on the suction line.

Incorrect: A restricted condenser raises high-side pressure and causes poor cooling, not frost on the suction line.

Incorrect: A restricted receiver-drier causes frost at the drier and low pressures, and the compressor would cycle off on low pressure.

Incorrect: An overcharge raises pressures and reduces cooling, but it does not freeze the evaporator and block airflow.

Correct: Holding the same road speed in different gears changes engine RPM while vehicle speed stays put: a vibration that stays follows the driveline, one that moves with RPM is engine-related.

Incorrect: A rough road surface adds suspension inputs and masks the vibration rather than isolating it.

Incorrect: Hard acceleration from a stop changes RPM and speed together, so it cannot separate the two.

Incorrect: Light braking adds brake inputs and tests the rotors, not whether a vibration follows RPM or road speed.

Incorrect: Tight circles load the CV joints and differential, but they do not separate RPM from vehicle speed.

Incorrect: A misadjusted pedal pushrod changes free play or causes drag; it does not let air into the booster or remove assist.

Incorrect: A restricted supply hose also starves the booster and hardens the pedal, but a blockage makes no hissing noise at the booster.

Correct: A torn diaphragm lets outside air bleed into the vacuum side, so the booster loses assist (hard pedal) and the leak is heard as a hiss at the booster itself.

Incorrect: The check valve was just tested and holds vacuum, so it is not the leak path behind the hiss.

Incorrect: Fluid bypassing the master cylinder seals makes the pedal sink under steady pressure; it does not raise pedal effort or make a vacuum hiss.

Correct: Worn piston cups let fluid slip past the piston inside the master cylinder bore, so pressure bleeds off and the pedal creeps down with no fluid lost outside.

Incorrect: Air makes the pedal spongy from the first push and firms up when pumped; it does not hold firm and then creep to the floor.

Incorrect: A leaking booster diaphragm reduces assist and makes the pedal harder; it does not let hydraulic pressure leak away.

Incorrect: Worn pads add travel before the pads touch the rotor, but after that the pedal holds; they cannot make it sink under constant pressure.

Incorrect: A clogged or collapsed hose traps pressure at a wheel and causes drag or pull; it cannot make the pedal sink.

Incorrect: 4.0 V is the drop across the supply wire itself, not the voltage left at the splice.

Incorrect: 12.0 V would only appear with no current flowing; a loaded supply wire always drops some voltage.

Incorrect: 6.0 V splits the 12 V evenly between wire and loads, but the 2 Ω load pair has twice the wire's resistance and gets two-thirds.

Incorrect: 10.0 V understates the wire drop; 4 A through 1 Ω loses 4 V, not 2 V.

Correct: The 6 Ω and 3 Ω loads in parallel equal 2 Ω, so 3 Ω total draws 4 A; the 1 Ω supply wire drops 4 V and leaves 8.0 V at the splice.

Incorrect: A slipping belt lowers system voltage, yet the battery holds 12.4 V; the loss sits between battery and bulb.

Incorrect: A bulb drawing extra current would pull the battery down, not hide a 2.2 V loss in the feed.

Incorrect: Overcharging would raise voltage and brighten the lamp; nothing here reads above 12.6 V.

Incorrect: A weak battery sags at its own posts; losing only 0.2 V there points away from the battery.

Correct: The bulb sees 2.2 V less than the battery terminals while lit, so the loss is in the wiring, connectors or switch between them.

Incorrect: A relief valve stuck open dumps oil back to the pan and gives low pressure, the opposite of this reading.

Correct: A relief valve that cannot open lets pump output build without limit, so the gauge reads high and the weakest seal, the filter gasket, lets go.

Incorrect: Extra main bearing clearance bleeds oil out of the galleries and lowers pressure everywhere.

Incorrect: A clogged pickup screen starves the pump inlet, which lowers pressure instead of raising it.

Incorrect: A bypass valve only routes oil around a clogged element; it cannot drive gallery pressure above normal on the gauge.

Incorrect: Carbon holding a valve off its seat leaks past the valve, which a wet test cannot cure.

Incorrect: Worn valve guides let oil into the chamber but do not cause a compression loss that oil on the rings can recover.

Correct: Oil temporarily seals the gap between worn rings and the bore, so a big jump from 95 to 140 psi points to the rings.

Incorrect: A burned exhaust valve leaks at the seat, and oil on the piston does nothing for a valve, so the wet reading would barely change.

Incorrect: A head gasket leak bypasses the rings entirely, so adding oil would not restore compression.

Incorrect: Clearing codes does the opposite to readiness: the monitors drop back to incomplete until they run again.

Incorrect: A code clear is a routine scan tool command; it erases stored data but does no harm to the module's memory hardware.

Correct: Clearing the codes also wipes the freeze-frame snapshot (rpm, load, temperature and trims at the moment the fault set), which is often the only record of when an intermittent stall happens.

Incorrect: Open or closed loop depends on sensor warm-up and operating conditions such as coolant temperature, not on whether codes were cleared.

Incorrect: On some vehicles a code clear resets transmission adaptive values, which simply relearn; nothing is corrupted, and the real loss is the fault snapshot.

Incorrect: Low pump volume shows up as low pressure under load while running, not as a leak-down after key-off.

Correct: With the supply line clamped the rail held pressure, so the leak is on the pump side of the clamp; a check valve that no longer seats lets fuel drain back to the tank.

Incorrect: A restricted fuel filter lowers pressure and volume while the pump runs; it does not make pressure bleed off after shutdown.

Incorrect: On this return-type rail the regulator sits past the clamp, so a leaking regulator would keep bleeding pressure even with the supply line clamped.

Incorrect: Fuel injector leakage happens on the rail side of the clamp, so pressure would still fall with the supply line pinched.