Five ASE G1 Auto Maintenance & Light Repair practice test questions, answers included.

1. Recall · Engine Systems

   After draining the oil and installing a new filter, a technician adds the oil capacity the manufacturer lists for an oil and filter change. Why is the engine then run briefly, shut off and given a few minutes before the dipstick is read and the level corrected?

   1. The drain plug gasket seats only under oil pressure
   2. The new filter and oil passages take up some oil
   3. Some fresh oil leaves through the PCV system at first
   4. The oil-life monitor resets only with the engine running
   Show the answer

   B. Correct. The empty new filter and the drained oil passages fill on the first run, so a level read right after filling is higher than it will be. A short run, a few minutes for the oil to drain back to the pan and then a dipstick reading let the technician top up to the full mark, and the filter and drain plug are checked for leaks at the same time.

   Why not the others

   A. The drain plug sits in the oil pan, which is not under pump pressure, and its gasket seals when the plug is torqued. The level drops after the first run because the empty filter and passages fill with oil.

   C. A working positive crankcase ventilation (PCV) system carries crankcase vapor, not liquid oil, to the intake, so it does not draw off a measurable amount of new oil. The drop comes from oil filling the new filter and passages.

   D. The oil-life monitor is reset by its own procedure and has nothing to do with the oil level. The engine is run to fill the new filter and passages, and the wait lets the oil drain back to the pan before it is read.

2. Recall · Manual Drive Train and Axles

   A front-wheel-drive half-shaft has a tripod-type inner constant velocity (CV) joint and a fixed ball-type outer CV joint. What does the inner joint allow that the outer joint does not?

   1. Large joint angles as the front wheel is steered
   2. Shaft length changes as the suspension moves
   3. Constant speed through the joint at an angle
   4. Different left and right wheel speeds in turns
   Show the answer

   B. Correct. As the wheel moves up and down, the distance between the transaxle and the wheel changes, and the inner joint's tripod slides in its housing to let the shaft plunge in and out. The fixed outer joint cannot plunge; its job is to work through the large angles of steering.

   Why not the others

   A. Working through large angles is the outer joint's job: the fixed ball-type joint at the wheel handles the steering angle as well as suspension travel. The inner tripod joint runs at smaller angles, and what it adds is plunge, letting the shaft's length change as the suspension moves.

   C. Both joints are constant velocity joints, so each passes speed through evenly at an angle, unlike a single universal joint. That is not what sets the inner joint apart; its tripod slides in the housing so the shaft can change length as the suspension moves.

   D. Letting the two front wheels turn at different speeds in a turn is the differential's job, not a CV joint's. The inner tripod joint lets the half-shaft change length as the suspension moves, which the fixed outer joint cannot do.

3. Recall · Suspension and Steering

   A vehicle has an indirect tire pressure monitoring system (TPMS), with no sensors inside the wheels. How does it detect a tire that is low on air?

   1. It sees that wheel turn slower than the other three
   2. It sees that wheel turn faster than the other three
   3. It receives a pressure signal from a valve-stem sensor
   4. It senses that corner of the body sitting lower
   Show the answer

   B. Correct. An indirect system works from the ABS wheel speed sensors: a tire low on air has a smaller rolling radius, so its wheel makes more turns per mile than the others and the module flags it. Because it judges the tires against each other, it is normally reset by the manufacturer's procedure after the pressures are set.

   Why not the others

   A. This is the effect reversed. Lower pressure shrinks the tire's rolling radius, so the wheel turns faster, not slower, at the same road speed; the system watches for the wheel that speeds up relative to the others.

   C. A valve-stem or band-mounted sensor that sends pressure by radio is a direct TPMS. An indirect system has no sensor in the wheel; it infers low pressure from the wheel speed signals.

   D. An indirect TPMS does not use ride height. It works from the ABS wheel speed signals, comparing how fast each wheel turns, and flags the one turning faster.

4. Recall · Brakes

   A vehicle has a pulsating brake pedal. Which tool is used to measure a front rotor's thickness variation?

   1. A dial indicator
   2. An outside micrometer
   3. An inside micrometer
   4. A straightedge and feeler gauge
   Show the answer

   B. Correct. Thickness variation is the difference between the thickest and thinnest readings taken at several points around the rotor, the same distance in from the edge, and the readings differ by ten-thousandths of an inch, so a micrometer is needed. Thickness variation is the condition a driver feels as pedal pulsation.

   Why not the others

   A. A dial indicator against the rotor face measures lateral runout, the side-to-side wobble as the rotor turns, not its thickness. Thickness variation is measured with an outside micrometer at several points around the rotor.

   C. An inside micrometer measures inside diameters, such as a cylinder bore; it cannot reach across the thickness between the rotor's two braking faces. That takes an outside micrometer.

   D. A straightedge and feeler gauge check a surface for flatness, as on a cylinder head; they cannot measure the small differences in thickness around a rotor. An outside micrometer read at several points does that.

5. Recall · Electrical

   A battery's top and terminals are crusted with white and green corrosion, and the technician washes them with a solution of baking soda and water. What does the solution do?

   1. Dissolves lead from the posts to brighten them
   2. Neutralizes the acid in the corrosion
   3. Leaves a film that stops new corrosion
   4. Removes surface charge from the battery
   Show the answer

   B. Correct. Battery corrosion holds sulfuric acid, and baking soda, a mild base, neutralizes it so it can be rinsed away safely; the fizzing stops when the acid is used up. The vent caps stay in place so none of the solution gets into the cells, where it would neutralize electrolyte and weaken the battery.

   Why not the others

   A. Baking soda does not dissolve lead; the posts and clamps are brightened with a post-and-clamp brush after washing. The solution's job is to neutralize the acid in the corrosion.

   C. The residue is rinsed off with clean water, not left as protection. After the clamps are tightened, a battery terminal protectant or grease is what slows new corrosion.

   D. Surface charge is a voltage effect at the plates inside the battery and is removed electrically, with a brief load, not by washing the case. The solution neutralizes the acid in the corrosion.

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