Practice Test GeeksASE4 - ASE Automobile Engine Performance Practice Test
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Engine Electrical Systems Flashcards

6 cards from real ASE4 practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.

Read the first 6 Engine Electrical Systems flashcards as text

  1. A vehicle with a smart charging system shows 12.6V on the scan tool but 14.4V on a voltmeter at the battery. The discrepancy is because:

    Answer: The BCM is reporting battery voltage, not alternator output voltage

    The scan tool reads the BCM's internal battery voltage sense circuit, while the voltmeter reads actual terminal voltage — these can differ due to sensor location or calibration.

  2. A no-start complaint: the engine cranks normally but will not start. Battery and charging tests are normal. The technician should next check:

    Answer: Spark, fuel pressure, and injector pulse with a noid light

    Normal crank speed with a no-start condition means the electrical starting circuit is good; the next step is to verify the three elements of combustion: spark, fuel, and injector control.

  3. Excessive AC ripple on the charging circuit (above 0.5 volts AC) can cause:

    Answer: ECM and module faults, erratic sensor readings, and communication errors

    AC ripple from a failing alternator diode introduces electrical noise that can disrupt ECM operation and cause numerous unrelated electronic faults.

  4. The purpose of the battery's CCA (Cold Cranking Amps) rating is to indicate:

    Answer: The current a battery can deliver at 0°F for 30 seconds while maintaining 7.2 volts

    CCA specifies the battery's ability to deliver high current at cold temperatures, directly reflecting its starting capability in winter conditions.

  5. A voltage drop test on the ground side of the starting circuit shows 0.6 volts. This indicates:

    Answer: Excessive resistance in the ground circuit reducing starter power

    Ground-side voltage drops above 0.1–0.2 volts indicate resistance that robs the starter of available voltage, causing slow or difficult cranking.

  6. A technician measures 14.1 volts at the battery with the engine running and all accessories on. This reading indicates:

    Answer: Normal charging system output

    A reading of 13.5–14.7 volts at the battery with the engine running is the normal charging system output range, indicating correct alternator operation.