Complete Study Guide for ASE A/C Certification
An EATC air conditioning system has low fan speed operation during high demand situations, like in
direct sunlight. Technician A says this is because something is covering the sun load sensor's photo
diode. Technician B says a sun load sensor is a variable resistor and can be tested with an ohmmeter.
Who is correct? - correct answer ✔✔Both A and B
A gurgling sound is heard coming from inside the dashboard of a vehicle. Technician A says this is air
trapped in the heater core. Technician B says this noise can be caused by a blown head gasket. Who is
correct? - correct answer ✔✔Both A and B
A manifold gauge indicates a system has low discharge pressure. The MOST likely cause of this condition
is: - correct answer ✔✔A damaged compressor reed valve.
The compressor is rapidly cycling on and off on a CCOT (cycling clutch orifice tube) 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? - correct answer ✔✔Both A and B
Technician A says while performing a retrofit from R-12 refrigerant to R134a refrigerant, the refrigerant
must be recovered into a dedicated cylinder, they cannot be mixed. Technician B says R-12 refrigerant
functions at higher pressures than R-134a refrigerant does. Who is correct? - correct answer ✔✔Tech A
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? -
correct answer ✔✔Tech B
During an initial inspection, the technician notices that one line on the receiver drier is cooler than the
other. This is caused by: - correct answer ✔✔A restriction in the receiver drier.
During a performance test on a CCOT system the manifold gauge indicates that the high side pressure is
low and the low side pressure is high. This is caused by a: - correct answer ✔✔Faulty compressor
, An air conditioning 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 system's
thermostat. Who is correct? - correct answer ✔✔Both A and B
Technician A says a fixed orifice tube varies the flow of refrigerant in relation to temperature. Technician
B says a fixed orifice tube is located between the condenser and the evaporator. Who is correct? -
correct answer ✔✔B Only (A fixed orifice tube provides a consistent output, based upon the size of its
orifice. It's a compromise between idle and highway conditions)
Technician A says the expansion valve is located on the inlet port of the evaporator. Technician B says the
expansion valve's temperature sensing bulb is located near the outlet port of the evaporator. Who is
correct? - correct answer ✔✔Both A and B
During a visual inspection an oily spot is found on a hose leading from the compressor. Technician A says
there may be a refrigerant 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? - correct answer ✔✔Tech A Only
An air conditioning system contains a thermostatic expansion valve. The suction line leading to the
compressor is cool to the touch. This indicates: - correct answer ✔✔Normal Condition
All of these are true about an accumulator EXCEPT: - correct answer ✔✔This system contains a
thermostatic expansion valve to meter the refrigerant.
A vehicle has poor air conditioning performance. The customer has added R134a refrigerant to the
system. Technician A says to use a refrigerant identifier. Technician B says refrigerant mixtures are not
recommended, but will not affect system pressures. Who is correct? - correct answer ✔✔Tech A Only
Two technicians are discussing a CCOT air conditioning system. Technician A says the system's pressure
cycling clutch switch contains a bulb placed on the inlet port of the evaporator core. Technician B says a
pressure cycling switch is located on the low side of the system. Who is correct? - correct answer
✔✔Tech B Only
All these statements are true about a throttle position sensor EXCEPT: - correct answer ✔✔The ECM
disengages the A/C clutch at idle.
An EATC air conditioning system has low fan speed operation during high demand situations, like in
direct sunlight. Technician A says this is because something is covering the sun load sensor's photo
diode. Technician B says a sun load sensor is a variable resistor and can be tested with an ohmmeter.
Who is correct? - correct answer ✔✔Both A and B
A gurgling sound is heard coming from inside the dashboard of a vehicle. Technician A says this is air
trapped in the heater core. Technician B says this noise can be caused by a blown head gasket. Who is
correct? - correct answer ✔✔Both A and B
A manifold gauge indicates a system has low discharge pressure. The MOST likely cause of this condition
is: - correct answer ✔✔A damaged compressor reed valve.
The compressor is rapidly cycling on and off on a CCOT (cycling clutch orifice tube) 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? - correct answer ✔✔Both A and B
Technician A says while performing a retrofit from R-12 refrigerant to R134a refrigerant, the refrigerant
must be recovered into a dedicated cylinder, they cannot be mixed. Technician B says R-12 refrigerant
functions at higher pressures than R-134a refrigerant does. Who is correct? - correct answer ✔✔Tech A
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? -
correct answer ✔✔Tech B
During an initial inspection, the technician notices that one line on the receiver drier is cooler than the
other. This is caused by: - correct answer ✔✔A restriction in the receiver drier.
During a performance test on a CCOT system the manifold gauge indicates that the high side pressure is
low and the low side pressure is high. This is caused by a: - correct answer ✔✔Faulty compressor
, An air conditioning 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 system's
thermostat. Who is correct? - correct answer ✔✔Both A and B
Technician A says a fixed orifice tube varies the flow of refrigerant in relation to temperature. Technician
B says a fixed orifice tube is located between the condenser and the evaporator. Who is correct? -
correct answer ✔✔B Only (A fixed orifice tube provides a consistent output, based upon the size of its
orifice. It's a compromise between idle and highway conditions)
Technician A says the expansion valve is located on the inlet port of the evaporator. Technician B says the
expansion valve's temperature sensing bulb is located near the outlet port of the evaporator. Who is
correct? - correct answer ✔✔Both A and B
During a visual inspection an oily spot is found on a hose leading from the compressor. Technician A says
there may be a refrigerant 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? - correct answer ✔✔Tech A Only
An air conditioning system contains a thermostatic expansion valve. The suction line leading to the
compressor is cool to the touch. This indicates: - correct answer ✔✔Normal Condition
All of these are true about an accumulator EXCEPT: - correct answer ✔✔This system contains a
thermostatic expansion valve to meter the refrigerant.
A vehicle has poor air conditioning performance. The customer has added R134a refrigerant to the
system. Technician A says to use a refrigerant identifier. Technician B says refrigerant mixtures are not
recommended, but will not affect system pressures. Who is correct? - correct answer ✔✔Tech A Only
Two technicians are discussing a CCOT air conditioning system. Technician A says the system's pressure
cycling clutch switch contains a bulb placed on the inlet port of the evaporator core. Technician B says a
pressure cycling switch is located on the low side of the system. Who is correct? - correct answer
✔✔Tech B Only
All these statements are true about a throttle position sensor EXCEPT: - correct answer ✔✔The ECM
disengages the A/C clutch at idle.
