ASE T6 Truck Electrical Prep practice questions and answers 2026. Tap an option to test yourself — you'll see the correct answer and a plain-English explanation for every question. Free, no login.
Q21A technician is measuring the voltage across a battery with the engine off. The reading is 12.4 volts. What is the approximate state of charge of this battery?
✓ Correct answer: D. 75%
A 12.4 volt reading indicates a battery that is approximately 75% charged. A fully charged battery typically reads 12.6-12.8 volts at rest.
Q22When conducting a battery load test, for how long should the load be applied?
✓ Correct answer: C. 15 seconds
The standard procedure for a battery load test is to apply the load for 15 seconds while monitoring voltage. This is sufficient time to evaluate the battery's performance without causing damage.
Q23A truck's batteries are being tested for capacity. If each battery is rated at 850 CCA (Cold Cranking Amps) and they are connected in parallel, what would be the total CCA capacity?
✓ Correct answer: B. 1,700 CCA
When batteries are connected in parallel, the amperage (CCA) adds together, while the voltage remains the same. Two 850 CCA batteries in parallel would provide 1,700 CCA.
Q24When performing a voltage drop test on a battery cable, the maximum acceptable voltage drop is:
✓ Correct answer: A. 0.2 volts
The industry standard for maximum acceptable voltage drop in a battery cable is 0.2 volts. Anything higher indicates excessive resistance in the circuit that requires attention.
Q25A truck's starter draws excessive current but cranks slowly. Technician A says this could be caused by a defective starter motor. Technician B says this could be caused by engine mechanical problems. Who is right?
✓ Correct answer: D. Both A and B
Both are correct. A defective starter motor with worn bushings or damaged armature can draw high current while cranking slowly. Mechanical engine problems like high compression or seized components can also cause slow cranking with high current draw.
Q26When jump-starting a truck with discharged batteries, the correct connection sequence is:
✓ Correct answer: C. Positive of good battery to positive of dead battery, then negative of good battery to negative of dead battery or engine ground
The proper jump-starting procedure is to connect positive to positive first, then the negative of the good battery to the negative of the dead battery or engine block/frame ground. This reduces the risk of sparks near the battery which could ignite hydrogen gas.
Q27A truck has multiple batteries that read 12.6 volts individually, but the voltage at the starter is only 10.5 volts during cranking. The most likely cause is:
✓ Correct answer: B. High resistance in the battery cables or connections
High resistance in the battery cables or connections will cause excessive voltage drop during high current draw situations like cranking, resulting in low voltage at the starter despite good battery voltage readings.
Q28When testing a battery with a digital multimeter, which setting should be used first?
✓ Correct answer: A. DC voltage
DC voltage is the first measurement to take when testing a battery, as it provides the battery's state of charge before conducting any load or other tests.
Q29A truck's batteries are in good condition, but the starter makes a single loud click and will not crank the engine. The most likely cause is:
✓ Correct answer: D. An open circuit in the starter motor
A single loud click typically indicates the solenoid is engaging but the starter motor is not turning. This is most commonly caused by an open circuit in the starter motor or poor connections within the starter assembly.
Q30What is the most accurate method to test for a parasitic battery drain?
✓ Correct answer: C. Connect a digital multimeter in series with the negative battery cable
Using a digital multimeter set to measure amps in series with the battery's negative cable is the most accurate method to measure parasitic drain. This allows precise measurement of the current draw with the vehicle off.
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Theory