ASE4 Engine Electrical Systems

Question 1

A technician performs a voltage drop test across a battery cable and finds 0.8 volts with the engine cranking. This indicates:

Accepted Answer

Excessive resistance in the cable causing a voltage drop concern

Answer

Acceptable voltage drop across a battery cable should be no more than 0.1–0.2 volts; 0.8 volts indicates significant resistance causing a power loss.

Question 2

What is the purpose of the alternator's voltage regulator?

Accepted Answer

To maintain charging voltage within a safe range regardless of engine speed

Answer

The voltage regulator controls alternator field current to maintain output voltage between approximately 13.5–14.7V regardless of RPM or load.

Question 3

A battery load test shows the voltage drops to 9.2 volts under load. This result indicates:

Accepted Answer

The battery failed and should be replaced

Answer

A battery that drops below approximately 9.6 volts during a load test has failed and cannot supply adequate current for reliable starting.

Question 4

An alternator output test shows only 12.8 volts at 2,000 RPM with lights and accessories on. Normal is 13.5–14.7V. This indicates:

Accepted Answer

Low alternator output requiring further diagnosis

Answer

Alternator output should be higher than battery voltage to charge it — 12.8V under load at speed indicates insufficient alternator output.

Question 5

A starter motor cranks the engine slowly. Battery tests good. The NEXT step is to:

Accepted Answer

Perform a starter current draw test and voltage drop tests on starter circuits

Answer

Slow cranking with a good battery requires testing starter current draw and voltage drops to distinguish between a faulty starter and high circuit resistance.

ASE4 - ASE Automobile Engine Performance Practice Test

ASE4 - ASE Automobile Engine Performance Practice Test

ASE4 Engine Electrical Systems