ASE A6 Electrical Electronics Practice Test

Voltage drop test

6. A vehicle's engine is slow cranking. The battery has 12.6V and is in good condition. A voltage drop test is performed to test the starter circuit. Technician A says the test result above indicates there is excessive resistance in this circuit. Technician B says the ignition must be disabled, and the starter cranked to perform this test. Who is correct?

  • A. Technician A
  • B. Technician B
  • C. Both A and B
  • D. Neither A or B

6.

Answer A is wrong. Both technician A and B are correct.

Answer B is wrong. Both technician A and B are correct.

Answer C is correct. Troubleshoot the cables, connections, and the solenoid in the starter circuit using voltage drop testing.

Answer D is wrong. Both technician A and B are correct.

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7. An engine is overheating. The electric radiator cooling fan in the illustration does not operate unless commanded ON with the scan tool. Technician A says the vehicle most likely has a faulty fan relay. Technician B says a faulty engine coolant temperature sensor or circuit would result in this condition. Who is correct?

  • A. Technician A
  • B. Technician B
  • C. Both A and B
  • D. Neither A or B
Simple fan circuit explained.

7.

Answer A is correct. The relay works when commanded ON by the scan tool.

Answer B is wrong. A problem with the engine coolant temperature circuit would result in this condition.

Answer C is wrong. Technician B is correct.

Answer D is wrong. Technician B is correct.

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8. The right backup light in the diagram above is dim. The other light is normal. Which of the following is causing this condition?

  • A. Resistance at point A.
  • B. An open at point B.
  • C. An open at point C.
  • D. Resistance at point D.

8.

Answer A is wrong. Resistance in the connection at point A results in dim (both) backup lights.

Answer B is wrong. An open circuit in the neutral safety switch results in inoperative backup lights.

Answer C is wrong. An open at point C results in an inoperative left-side backup light.

Answer D is correct. Excessive resistance in the connection at point D results in a dim right-side backup light.

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9. The resistance between pins 6 and 14 of the OBD II connector above measures 60 ohms. Technician A says this is correct. Technician B says the modules must be powered down or the battery disconnected to test resistance in the CAN bus. Who is correct?

  • A. Technician A
  • B. Technician B
  • C. Both A and B
  • D. Neither A or B

9.

Answer A is wrong. CAN buses use twisted pair wires that reduce noise and interference. Twisted pair wire has an impedance of around 120 ohms.

Answer B is wrong. All modules must be powered down, or the vehicle's battery disconnected to measure resistance in the CAN bus circuit. Testing a powered circuit can damage the ohmmeter.

Answer C is correct. To prevent reflection, the CAN bus has two 120 Ohm resistors placed in parallel. They are often inside a control module like the ECM. This configuration results in 60 Ohms of resistance on the bus.

Answer D is wrong. Learn more about the CAN bus by clicking the Read more button.

10. A vehicle's air conditioner blower motor only works if the selector is in the high position. Technician A says to check the blower motor resistor. Technician B says this is most likely a loose ground connection. Who is correct?

  • A. Technician A
  • B. Technician B
  • C. Both A and B
  • D. Neither A or B

10.

Answer A is correct. A blower motor resistor uses resistance to control blower motor speeds.

Answer B is wrong. Typically a loose connection causes an intermittent condition.

Answer C is wrong. Technician A is correct.

Answer D is wrong. Technician A is correct.