On-Vehicle Inspection [02/2019 - ]: Procedure

1. Install the air conditioning tool set to the vehicle.
2. Set the vehicle to the following conditions. [*1]

   Item	Condition
   Vehicle Body	Vehicle stopped in shade
   Door	Fully open
   A/C Switch	ON
   Fresh/recirculation Mode Control Damper Position	Recirculation
   Air Vent Damper Position	FACE
   Set Temperature	MAX COLD
   Blower Speed	HI
   Air Conditioning Air Inlet Temperature*2	25 to 34°C (77 to 93.2°F)
   Condenser Pressure (Gauge High Pressure Side)*3	1.37 to 1.57 MPaG (14 to 16 kgf/cm2 )

   HINT: 

   *2: This inspection can be judged correctly only if the air inlet temperature is within a range of 25 to 34°C (77 to 93.2°F). Therefore, postpone the test if the temperature is low.

   If the condenser pressure (gauge high pressure side) is high, splash the condenser with water to lower the pressure. Conversely, if the condenser pressure is low, cover the front of the condenser to raise the pressure.

3. Place a wet and dry bulb thermometer at the air inlet (necessary for measuring the humidity), and insert its dry bulb at the center of the air vent to measure.
4. Operate the air conditioning in the conditions of [*1], and allow the temperature at the air vent to stabilize. (Approximately 5 to 6 minutes)
5. Measure the wet and dry temperatures of the air inlet and the temperature of the air vent.
6. Map the measurement values of the air inlet to the psychometric diagram to find the relative humidity.

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

   *a	Psychrometric Diagram	*b	Dry Bulb Temperature (°C)
   *c	Wet Bulb Temperature (°C)	*d	Relative Humidity (%)

   1. One way of finding the relative humidity is to find the intersection point of the wet and dry bulb temperatures, 19.5°C and 25°C, respectively, of the wet and dry bulb thermometer set at the air inlet. In this case, the relative humidity is 60%.

      Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

      *a	Example
      *b	Dry Bulb Temperature (°C)
      *c	Wet Bulb Temperature (°C)

7. Check the cooling performance by mapping the relative humidity and the difference between the measured dry bulb temperatures of the air inlet and air vent in the standard performance chart.

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

   *a	Standard Performance Chart	*b	Air Inlet/air Vent Temperature Difference (°C)
   *c	Relative Humidity (%)	-	-

   Standard

   Must be within the range between the diagonal lines in the chart.

   1. One example of how to check the cooling performance using a standard performance chart is to find the intersection point of the relative humidity (60%) and the difference in dry bulb temperatures at the air inlet and vent (17°C). In this example, the cooling performance is inside the standard range.

      Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

      *a	Example
      *b	Air inlet/air vent temperature difference (°C)
      *c	Relative humidity (%)
      *d	Intersection

1. Check refrigerant pressure using gauge.

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

   *a	Pressure on Low Pressure Side kPa (kgf/cm2 , psi)	*b	Pressure on High Pressure Side kPa (kgf/cm2 , psi)
   *c	Blower High Zone	*d	Blower Low Zone

   1. Install the air conditioning tool set.
   2. Set the vehicle to the following conditions. [*3]
      MEASUREMENT CONDITION:
      
      

      Item	Condition
      Vehicle Condition	Ignition switch ON (READY)
      Door	Fully closed (windows also fully closed)
      A/C Switch	On
      Recirculation/fresh Control Switch	Recirculation
      Set Temperature	MAX COLD
      Blower Speed	HI
      Air Conditioning Air Inlet Temperature	25 to 35°C (77 to 95°F)

   3. In conditions [*3], read the gauge and check the numerical value.
      1. Normal

         Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

         *a	LO
         *b	HI

         Specified Condition

         GAUGE READING
         
         

         Pressure Side	Refrigerant Volume
         Low	150 to 250 kPa (1.5 to 2.5 kgf/cm2 , 22 to 36 psi)
         High	1370 to 1570 kPa (14.0 to 16.0 kgf/cm2 , 199 to 228 psi)

         HINT: 

         The illustration shows the gauges when the refrigerant gas volume is normal.

      2. During malfunction
         1. Symptom 1: During cooling operation, pressure on low pressure side cycles between normal and vacuum.

            Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

            *a	LO
            *b	HI

            STANDARD VALUE MEASUREMENT RESULT
            
            

            Symptom	The air conditioning system works intermittently
            Cause	Moisture in the cooling system freezes at the cooler expansion valve orifice and temporarily prevents refrigerant gas from circulating. The condition, however, is restored to normal after the ice is melted.
            Diagnosis	Cooler dryer is overly saturated Moisture in the cooling system freezes at the cooler expansion valve orifice and blocks circulation of the refrigerant gas
            Action Taken	Replace the cooler dryer Remove moisture from cycle by repeatedly evacuating air Add an appropriate volume of new refrigerant gas

            HINT: 

            The illustration shows the gauges when moisture has gotten into the cooling system.

         2. Symptom 2: The pressure on both the low and high pressure sides is low.
            STANDARD VALUE MEASUREMENT RESULT
            
            

            Symptoms	Cooling is not working well Coolant performance is insufficient
            Cause	There is a gas leak somewhere in the cooling system
            Diagnosis	Insufficient refrigerant gas volume Refrigerant gas leak
            Action Taken	Check for refrigerant gas leak and repair if necessary Refer to REMOVAL [02/2019 - 08/2020] , or refer to REMOVAL [08/2020 - 12/2021] , or refer to REMOVAL [12/2021 - ] Add an appropriate volume of new refrigerant gas If the pressure readout value when the gauge is connected is near 0, check for leaking points, make necessary repairs, and then evacuate the air conditioning system

            HINT: 

            The illustration shows the gauges when cooling is not working well.

            Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

            *a	LO
            *b	HI

         3. Symptom 3: The pressure on both the low and high sides is low, which causes condensation on the pipe from the cooler condenser assembly to the A/C unit.

            Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

            *a	LO
            *b	HI

            STANDARD VALUE MEASUREMENT RESULT
            
            

            Symptoms	Cooling is not working well
            Cause	Dust in the cooler condenser core blocks the flow of refrigerant gas
            Diagnosis	Blockage of cooler condenser core
            Action Taken	Replace the cooler condenser assembly

            HINT: 

            The illustration shows the gauges when cooling by refrigerant gas is not working well.

         4. Symptom 4: The pressure on both the low and high sides is low, which causes frost or condensation on the pipe before and after the cooler condenser core or cooler expansion valve.

            Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

            *a	LO
            *b	HI

            STANDARD VALUE MEASUREMENT RESULT
            
            

            Symptoms	Cooling is not functioning (also functioning occasionally)
            Cause	The flow of refrigerant gas is blocked by moisture or dust in the cooling system The flow of refrigerant gas is impaired by refrigerant gas leak from the cooler expansion valve
            Diagnosis	Refrigerant gas cannot circulate
            Action Taken	Check the cooler expansion valve Remove dust in the cooler expansion valve with an air gun Replace the cooler condenser assembly Evacuate the air conditioning system, and then add an appropriate volume of new refrigerant gas If there is a refrigerant gas leak from the cooler expansion valve, replace the valve

            HINT: 

            The illustration shows the gauges when refrigerant gas does not circulate.

         5. Symptom 5: The pressure on both the low and high pressure sides is high.

            Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

            *a	LO
            *b	HI

            STANDARD VALUE MEASUREMENT RESULT
            
            

            Symptoms	Cooling is not working well
            Cause	The flow of refrigerant gas is blocked by moisture or dust in the cooling system The flow of refrigerant gas is impaired by refrigerant gas leak from the cooler expansion valve
            Diagnosis	Excessive refrigerant gas volume Cooling of cooler condenser core is insufficient
            Action Taken	Clean the cooler condenser core fin Check the operation of the condenser fan Adjust the refrigerant gas volume

            HINT: 

            The illustration shows the gauges when the refrigerant gas volume is excessive or cooling of the cooler condenser core is insufficient.

         6. Symptom 6: The pressure on both the low and high pressure sides is high, and the low pressure line is too hot to touch.

            Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

            *a	LO
            *b	HI

            STANDARD VALUE MEASUREMENT RESULT
            
            

            Symptoms	Cooling is not functioning
            Cause	Air in refrigeration system
            Diagnosis	Air is in the refrigeration system Evacuation of the air conditioning system is insufficient
            Action Taken	Check if the compressor oil is dirty or insufficient Evacuate the air conditioning system, and then add an appropriate volume of new refrigerant gas

            HINT: 

            • Notes: The gauge indicates when the cooling system is open without the system being evacuated and filled with refrigerant gas.
            • The illustration shows the gauges when air has gotten into the refrigerant system.
         7. Symptom 7: The pressure on both the low and high pressure sides is high, and frost or condensation is forming on the low pressure side.

            Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

            *a	LO
            *b	HI

            STANDARD VALUE MEASUREMENT RESULT
            
            

            Symptoms	Cooling is not working well
            Cause	Trouble with the cooler expansion valve
            Diagnosis	Refrigerant gas volume is excessive on the low pressure pipe line Cooler expansion valve opened too far
            Action Taken	Replace the cooler expansion valve

            HINT: 

            The illustration shows the gauges when the cooler expansion valve is improper.

         8. Symptom 8: The pressure on the low pressure side is high and the pressure on the high pressure side is low.

            Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

            *a	LO
            *b	HI

            STANDARD VALUE MEASUREMENT RESULT
            
            

            Symptoms	Cooling is not functioning
            Cause	Compression leak inside the compressor with motor assembly
            Diagnosis	Compression malfunction Valve leak or damaged sliding parts
            Action Taken	Repair or replace the compressor with motor assembly

            HINT: 

            The illustration shows the gauges when the compression in the compressor with motor assembly is poor.

         9. Symptom 9: The pressure is the same on both the low and high pressure sides.

            Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

            *a	LO
            *b	HI

            STANDARD VALUE MEASUREMENT RESULT
            
            

            Symptoms	Cooling is not functioning
            Cause	Trouble with the compressor with motor assembly
            Diagnosis	Compressor with motor assembly does not rotate
            Action Taken	Repair or replace the compressor with motor assembly

            HINT: 

            The illustration shows the gauges when the compressor with motor assembly is malfunctioning.

1. When the fins of the cooler condenser assembly are dirty, clean with water and dry with compressed air.
   NOTE:

   • Do not damage the cooler condenser assembly fins.
   • When the cooler condenser assembly fins are bent, use a screwdriver or pliers to straighten them.

1. Using a halogen leak detector, check for refrigerant gas leaks from connections on the pipe line.
2. If refrigerant gas is leaking from a connection on the pipe line, check the tightening torque of the joint.

HINT: 

Depending on the environment (condition), the actual control may not change in some situations even if ECO drive mode is activated.

1. Check that the indicator illuminates and airflow volume from the air outlet is controlled when the integration control and panel assembly (ECO switch) is turned on.
2. Check that the indicator light turns off and that airflow control is canceled when the integration control and panel assembly (ECO switch) is turned off.