Ase Test Prep

1. During an A/C performance test on a fixed orifice tube A/C system, the manifold gauge indicates that the high side pressure is low, and the low side pressure is high. This is caused by a:

A stuck open expansion valve.

B frozen expansion valve.

C restricted condenser.

D faulty compressor.

6. Technician A says oil residue on an A/C hose may indicate a leak in the system. Technician B says today’s R134a systems use mineral oil instead of the older R12 compatible PAG oil. Who is correct?

A Technician A

B Technician B

C Both A and B

D Neither Technician A or B

2. An A/C system blows only warm air when the heater is on high output. Technician A says this could be a faulty heater control valve . Technician B says this could be caused by the cooling systems thermostat. Who is correct?

A Technician A

B Technician B

C Both A and B

D Neither Technician A or B

7. An A/C system contains a thermostatic expansion valve. The suction line leading to the compressor is cool to the touch. This indicates:

A a stuck open expansion valve.

B a low refrigerant charge.

C a stuck closed expansion valve.

D a normal condition.

3. Technician A says a fixed orifice tube varies the flow of refrigerant in relation to temperature. Technician B says the fixed orifice tube is located between the condenser and the evaporator. Who is correct?

A Technician A

B Technician B

C Both A and B

D Neither Technician A or B

8. All of these are true about an accumulator except:

A it is located on the low side of the system.

B it prevents excess liquid from entering the compressor.

C it contains a desiccant capable of absorbing moisture from the refrigerant.

D this A/C system contains a thermostatic expansion valve to meter the refrigerant.

4. Technician A says the expansion valve is located on the inlet port of the evaporator. Technician B says the expansion valves temperature sensing bulb is located near the outlet port of the evaporator. Who is correct?

A Technician A

B Technician B

C Both A and B

D Neither Technician A or B

9. A vehicle has poor A/C performance. The customer states that the system may have R12 and R134a refrigerants mixed together in the system. Technician A says to use a refrigerant identifier. Technician B says this mixture is not recommended, but will not effect system pressures. Who is correct?

A Technician A

B Technician B

C Both A and B

D Neither Technician A or B

5. Technician A says evacuating an A/C system will remove air, debris, and moisture. Technician B says to evacuate the system any time it’s been exposed to the atmosphere. Who is correct?

A Technician A

B Technician B

C Both A and B

D Neither Technician A or B

10. A customer just had his air conditioner repaired, and complains that it performs poorly during the hottest times of the day. Technician A says leaving the receiver drier exposed to the atmosphere too long will result in this condition. Technician B says there may be moisture in the system. Who is correct?

A Technician A

B Technician B

C Both A and B

D Neither Technician A or B

11. An air conditioning system with a variable displacement compressor has poor performance in high demand situations. All of these could be the cause except:

A. a low refrigerant charge.

B. a faulty control valve.

C. a faulty low pressure switch.

D. a weak compressor.

16. A compressor clutch coil is being tested. There are 12 volts at the connector and the ground is good. The resistance of the coil is 0.00 Ohms. Technician A says the coil has an open in it’s windings. Technician B says the clutch coil has a short and has failed the resistance test. Who is correct?

A. Technician A

B. Technician B

C. Both Technicians A and B

D. Neither Technician A or B

12. Technician A says an A/C clutch relay protects the control head from the clutch circuits high current. Technician B says a faulty relay will result in no A/C clutch operation. Who is correct?

A. Technician A

B. Technician B

C. Both Technician A and B

D. Neither Technician A or B

17. A vehicle’s air conditioner blows cold air at normal speeds, but warm air while sitting at stop lights. The least-likely cause of this conditon is:

A. an overheating engine.

B. a weak electric fan motor.

C. a frozen expansion valve.

D. debris in the condenser fins.

13. All of these are true about an A/C evaporator except:

A. it removes humidity from the air.

B. refrigerant flows from the bottom to the top.

C. refrigerant enters the core as a liquid.

D. the refrigerant changes from a vapor to a liquid as it receives heat from the cabin air.

18. The carpet is wet on the passenger’s side of a vehicle. Technician A says this may be caused by a leaking heater core. Technician B says this could be caused by a clogged evaporator case drain tube. Who is correct?

A. Technician A

B. Technician B

C. Both Technicians A and B

D. Neither Technician A or B

14. Technician A says the refrigerant always flows from the top of the A/C condenser to the bottom. Technician B says a restriction in an A/C condenser can cause damage to the compressor. Who is correct?

A. Technician A

B. Technician B

C. Both Technician A and B

D. Neither Technician A or B

19. The in-cabin temperature sensor is suspected for a vehicle’s poor A/C performance. Technician A says the in-cabin temperature sensor is an NTC that should be tested for resistance with an ohmmeter. Technician B says the aspirator may be disconnected from the vent system. Who is correct?

A. Technician A

B. Technician B

C. Both Technicians A and B

D. Neither Technician A or B

15. An A/C blower motor only operates in high speed. Technician A says there could be a short in the motors power feed. Technician B says it may have a faulty blower resistor. Who is correct?

A. Technician A

B. Technician B

C. Both Technician A and B

D. Neither Technician A or B

20. A TXV (thermostatic expansion valve) system blows cold air for about five minutes before it goes warm. Technician A says this could be caused by a low refrigerant charge. Technician B says there could be moisture in the system. Who is correct?

A. Technician A

B. Technician B

C. Both Technicians A and B

D. Neither Technician A or B

21. Two technicians are discussing inputs to an automatic temperature control system. Technician A says a sun load sensor is a photo sensitive diode. Technician B says a sun load sensor is a variable resistor. Who is correct?

A. Technician A

B. Technician B

C. Both Technician A and B

D. Neither Technician A or B

26. Technician A says while performing an R-12 retrofit, all R-12 refrigerant must be recovered into a dedicated, approved cylinder. Technician B says R-12 refrigerant functions at higher pressures than R-134a refrigerant does. Who is correct?

A. Technician A

B. Technician B

C. Both Technicians A and B

D. Neither Technician A or B

22. A gurgling sound is coming from inside the dashboard of a vehicle. Technician A says this may be air trapped in the heater core. Technician B says this noise can be caused by a blown head gasket. Who is correct?

A. Technician A

B. Technician B

C. Both Technician A and B

D. Neither Technician A or B

27. Technician A says an ambient temperature sensor senses cabin air temperature. Technician B says a faulty ambient temperature sensor can prevent compressor clutch engagement. Who is correct?

A. Technician A

B. Technician B

C. Both Technician A and B

D. Neither Technician A or B

23. A manifold gauge indicates a system has low discharge pressure. The most likely cause of this condition is:

A. a restricted condenser.

B. a loose fan belt.

C. a damaged reed valve.

D. a broken piston.

28. During an initial inspection, the technician notices that one line on the receiver drier is cooler than the other. This is most likely:

A. a normal condition.

B. a low refrigerant charge.

C. too much oil in the system.

D. a restriction in the receiver drier.

24.

There is a short to ground at point D of the electrical diagram above. Which of the following statements is true?

A. The clutch would not engage when powered.

B. The relay would remain open.

C. The PCM would not receive a signal from the clutch.

D. The clutch would engage whenever powered.

29.

The electrical symbol in the image represents:

A. a thermistor.

B. a connector.

C. a transistor.

D. a variable resistor.

25. The compressor is rapidly cycling on and off on a CCOT air conditioning system. Technician A says this condition can be caused by a low refrigerant charge. Technician B says this could be caused by a faulty clutch cycling switch. Who is Correct?

A. Technician A

B. Technician B

C. Both Technician A and B

D. Neither Technician A or B

30. Two technicians are discussing refrigerant storage. Technician A says HFC-134a is contained in a sky blue container. Technician B says CFC-12 is contained in a white container. Who is correct?

A. Technician A

B. Technician B

C. Both Technicians A and B

D. Neither Technician A or B