Toyota Avalon (XX50) 2019-2022 Service & Repair Manual: Problem Symptoms Table

PROBLEM SYMPTOMS TABLE

HINT:

  • Use the table below to help determine the cause of problem symptoms. If multiple suspected areas are listed, the potential causes of the symptoms are listed in order of probability in the "Suspected Area" column of the table. Check each symptom by checking the suspected areas in the order they are listed. Replace parts as necessary.
  • Inspect the fuses and relays related to this system before inspecting the suspected areas below.

VEHICLE CHECK ITEMS

HINT:

  • You can reduce the number of systems to check by using the results of the following operation check
  • Perform the following checks based on Customer Feedback and the vehicle condition.
  • The customer's opinion may not be consistent with the actual problem (eg: the cooling performance of the air conditioner is bad → actually, the wind volume is weak). It is important to check the problem symptoms accurately and judge correctly based on various sources of information.
  • Judgment as to whether the air conditioner panel is normal or abnormal can be judged by checking if the indicator illuminates or turns off when the switch is operated.
  • During servo motor initialization, the AUTO indicator light comes on, and then goes off when initialization has finished.
  • If the performance of the air conditioner is poor or there is a foul odor, check for clogging in the clean air filter.

Malfunction Operation/Function:

Common Function of Cool and Heater Function

Only Cool Air Function

Only Heater Function

Suspected Area

A/C Switch Operation

Blower Operation

Recirculation/Fresh Function

Air Outlet Changing Function

x

o

o

o

x

x

Go to "Problem Symptoms Table: Air Conditioning Control"

o

o

o

o

x

o

Go to "Problem Symptoms Table: Cooling Function"

o

o

o

o

o

x

Go to "Problem Symptoms Table: Heater Function"

o

x

o

o

x

x

Go to "Problem Symptoms Table: Blower Control"

o

o

x

o

x

x

Go to "Problem Symptoms Table: Air Inlet Control"

o

o

o

x

x

x

Go to "Problem Symptoms Table: Air Outlet Control"

x

x

x

x

x

x

Air Conditioning Amplifier Assembly or Air Conditioning Assembly is Defective

AIR CONDITIONING CONTROL

Symptom

Suspected Area

Link

Air conditioning system cannot be operated using air conditioning control panel (radio and display receiver assembly)

  • (With the exception of the switch indicators, no inputs are reflected when other switches operated)
  • Air conditioning amplifier assembly
  • Air conditioning control panel (radio and display receiver assembly)

Air conditioning system cannot be operated using air conditioning control panel (radio and display receiver assembly)

  • (Air conditioning system display operates)

Air conditioning control panel (radio and display receiver assembly)

Air conditioning system cannot be operated using air conditioning control panel (radio and display receiver assembly) immediately after starting the engine

  • (Air conditioning system display operates)
  • (Only AUTO indicator illuminates)
  • (A/C switch indicator does not illuminate)

Refer to "INITIALIZATION"

A/C switch indicator does not illuminate

  • Air conditioning amplifier assembly
  • Air conditioning control panel (radio and display receiver assembly)
  • A/C switch
  • A/C switch indicator
  • Servo motor
  • Damper and damper link
  • Refrigerant pressure
  • Ambient temperature

COOLING FUNCTION

Symptom

Suspected Area

Link

No cool air comes out

  • (Blower control is normal)
  • Cooler compressor assembly
  • Refrigerant pressure
  • Refrigerant volume
  • Cooler condenser assembly
  • Cooling fan system
  • Damper and damper link
  • No. 1 cooler thermistor
  • High inlet air temperature

  • Cooling effectiveness is poor
  • Cooling response is slow
  • ECO switch assembly (electric parking brake switch assembly)
  • Cooler compressor assembly
  • Refrigerant volume
  • Cooler condenser assembly
  • Cooling fan system
  • Damper and damper link
  • Automatic light control sensor
  • High inlet air temperature
  • Harness or connector

Temperature of outlet air is cooler on left or right side

  • (when same temperature set for both sides)
  • Cooler compressor assembly
  • Refrigerant volume
  • Damper and damper link
  • Automatic light control sensor
  • Harness or connector

  • Compressor assembly with pulley does not stop operating
  • Refrigerant pressure does not decrease when A/C switch is turned off
  • Short to +B in air conditioning amplifier assembly circuit
  • MG CLT relay
  • Magnet clutch assembly

HEATER FUNCTION

Symptom

Suspected Area

Link

  • No warm air comes out

    (Blower control is normal)

  • Outlet air temperature does not increase

    (Blower control is normal)

  • Engine coolant temperature
  • Refrigerant volume
  • No. 1 air conditioning radiator damper servo sub-assembly
  • Damper and damper link
  • Warm-up control
  • Blockage in heater radiator unit sub-assembly
  • Heater radiator unit sub-assembly

Temperature of outlet air is warmer on left or right side

  • (when same temperature set for both sides)
  • Damper and damper link
  • Blockage in heater radiator unit sub-assembly
  • Harness or connector

BLOWER CONTROL

Symptom

Suspected Area

Link

Blower motor does not operate at all

  • (Air does not blow from registers)
  • Blower motor with fan sub-assembly
  • Air conditioning amplifier assembly
  • Warm-up control
  • Engine coolant temperature sensor
  • Harness or connector

Airflow volume cannot be changed

  • Air conditioning amplifier assembly
  • Blower motor with fan sub-assembly
  • Harness or connector

  • Airflow volume is constantly low
  • Airflow volume sometimes becomes low
  • Blower motor with fan sub-assembly
  • ECO switch assembly (electric parking brake switch assembly)
  • Clean air filter
  • No. 1 cooler evaporator sub-assembly or heater radiator unit sub-assembly fins
  • No. 1 cooler thermistor
  • Aspirator

AIR INLET CONTROL

Symptom

Suspected Area

Link

  • Air inlet mode changes between recirculation/fresh randomly
  • Recirculation/fresh switch indicator is blinking
  • Customize setting*
  • Ambient temperature
  • Refrigerant pressure
  • Air conditioner pressure sensor circuit
  • Engine coolant temperature

  • Air inlet mode cannot be changed between recirculation/fresh
  • Air inlet mode does not change between recirculation/fresh automatically
  • No. 1 blower damper servo sub-assembly
  • Damper link
  • Air inlet damper mechanically locked
  • Engine coolant temperature
  • Air conditioner unit assembly

  • *: except USA and Canada

AIR OUTLET CONTROL

Symptom

Suspected Area

Link

Air outlet mode cannot be changed

  • (air outlet display changes)
  • No. 1 air conditioning radiator damper servo sub-assembly
  • Damper link
  • Air conditioner unit assembly

Air outlet mode cannot be changed

  • (air outlet display does not change)

Air conditioning control panel (radio and display receiver assembly)

DEFROSTER CONTROL

Symptom

Suspected Area

Link

Windshield frequently fogs up

  • Cooler compressor assembly
  • Refrigerant volume
  • Cooler expansion valve
  • No. 1 air conditioning radiator damper servo sub-assembly
  • Damper and damper link

    Precaution

    Recirculated/Fresh Air Modes do not Switch

    See More:

    Toyota Avalon (XX50) 2019-2022 Service & Repair Manual > Window Defogger System(for Hv Model): Parts Location
    PARTS LOCATION ILLUSTRATION *1 DEF RELAY *2 REAR WINDOW DEFOGGER WIRE *3 NO. 1 ENGINE ROOM RELAY BLOCK AND NO. 1 JUNCTION BLOCK ASSEMBLY - DEF FUSE *4 BACK WINDOW GLASS ILLUSTRATION *1 REAR WINDOW DEFOGGER SWITCH (RADIO AND DISPLAY RECEIVER ASSEMBLY) *2 DLC3 *3 AIR CONDITIONING AMPLIFIER ASSEMBLY *4 ...

    Toyota Avalon (XX50) 2019-2022 Owners Manual

    Toyota Avalon (XX50) 2019-2022 Service & Repair Manual

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