On-Vehicle Inspection

WARNING: This page is about a different car, the 2008 Toyota Yaris. However, it is still accessible from the selected car via links, so may be relevant.

INSPECT REFRIGERANT VOLUME

Check the sight glass on liquid tube sub-assembly A.

Test conditions:

Engine running at 1,500 RPM.
Blower speed control switch at HI.
A/C switch ON.
Temperature control lever in MAX. COLD position.

All doors fully open.

Fig 1: Identifying Sight Glass On Liquid Tube Sub-Assembly

Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

PROBLEM SYMPTOMS CHART

Item	Symptom	Amount of Refrigerant	Corrective Procedures
1	Bubbles visible	Insufficient*	Check for gas leakage and repair if necessary Add refrigerant until bubbles disappear
2	No bubbles visible	Empty, insufficient or too much	Refer to items 3 and 4
3	No temperature difference between compressor inlet and outlet	Empty or nearly empty	Check for gas leakage with gas leak detector and repair if necessary Add refrigerant until bubbles disappear
4	Considerable temperature difference between compressor inlet and outlet	Correct or too much	Refer to items 5 and 6
5	Immediately after A/C turned OFF, refrigerant becomes clear	Too much	Drain or discharge refrigerant Bleed air and supply proper amount of purified refrigerant
6	Immediately after A/C turned OFF, refrigerant foams and then becomes clear	Correct	-

HINT:

*: If the ambient temperature is higher than usual but cooling is sufficient, bubbles in the sight glass are permissible.

CHECK REFRIGERANT PRESSURE USING MANIFOLD GAUGE SET

This is a method to identify trouble areas by using a manifold gauge set. Read the manifold gauge pressure under the following conditions.

Test conditions:

Engine warm.
All doors fully open.
A/C switch ON.
Blower speed control switch at HI.
Engine running at 1,500 RPM.
Air inlet mode damper set at recirculation.
Temperature control lever in MAX. COLD position.
Air temperature at air inlet 30 to 35°C (86 to 95°F).

When the refrigerant volume is correct, the gauge reading indicates as follows:
Low pressure side: 0.15 to 0.25 MPa (1.5 to 2.5 kgf/cm ² )

High pressure side: 1.37 to 1.57 MPa (14 to 16 kgf/cm ² )

HINT:

Pressure varies in accordance with certain conditions (outside air temperature, sunlight and wind).

When there is moisture in the refrigeration system:

Fig 2: Identifying Manifold Gauge Set

Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

Fig 3: Checking Refrigerant Pressure - Moisture In Refrigeration System

Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

DIAGNOSTIC NOTE AND MEASUREMENT ITEM / DISPLAY RANGE

Symptoms	Probable Cause	Diagnosis	Corrective Actions
During operation, pressure on low pressure side cycles between normal and vacuum	Moisture in refrigeration system freezes at expansion valve orifice, causing temporary interruption of cycle However, when melted, returns to normal condition	Receiver dryer oversaturated Moisture in refrigeration system freezes at expansion valve orifice and blocks refrigerant circulation	Replace receiver dryer Remove moisture from cycle by repeatedly evacuating air Supply appropriate volume of new refrigerant

When cooling is insufficient:

Fig 4: Checking Refrigerant Pressure - Cooling Is Insufficient

Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

DIAGNOSTIC NOTE AND MEASUREMENT ITEM / DISPLAY RANGE

Symptoms	Probable Cause	Diagnosis	Corrective Actions
Pressure low on both low and high pressure sides Cooling performance insufficient	Gas leakage from refrigeration system	Insufficient refrigerant Refrigerant leakage	Check for gas leakage using gas leak detector, and repair if necessary Supply appropriate volume of new refrigerant If indicated pressure value close to 0 when connected to gauge, create vacuum after inspecting and repairing location of leakage

When the circulation of the refrigerant is poor:

Fig 5: Checking Refrigerant Pressure - Circulation Of Refrigerant Poor

Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

DIAGNOSTIC NOTE AND MEASUREMENT ITEM / DISPLAY RANGE

Symptoms	Probable Cause	Diagnosis	Corrective Action
Pressure low on both low and high pressure sides Frost exists on piping from condenser to A/C unit	Refrigerant flow obstructed by dirt in condenser	Condenser clogged	Replace condenser

When the refrigerant does not circulate:

Fig 6: Checking Refrigerant Pressure - Refrigerant Not Circulate

Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

DIAGNOSTIC NOTE AND MEASUREMENT ITEM / DISPLAY RANGE

Symptoms	Probable Causes	Diagnosis	Corrective Actions
Vacuum indicated on low pressure side, and extremely low pressure indicated on high pressure side Frost or condensation seen on piping on both sides of condenser or expansion valve	Refrigerant flow obstructed by moisture or dirt in refrigeration system Refrigerant flow obstructed by gas leakage from expansion valve	Refrigerant does not circulate	Check expansion valve Clean expansion valve with compressed air Replace condenser Evacuate air and then supply appropriate volume of new refrigerant For gas leakage from expansion valve, replace expansion valve

When the refrigerant is overcharged or cooling of condenser is insufficient:

Fig 7: Checking Refrigerant Pressure - Refrigerant Overcharged

Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

DIAGNOSTIC NOTE AND MEASUREMENT ITEM / DISPLAY RANGE

Symptoms	Probable Causes	Diagnosis	Corrective Actions
Pressure extremely high on both sides	Excessive refrigerant Cooling performance of condenser insufficient	Excessive refrigerant Cooling performance of condenser insufficient	Clean condenser fins Check condenser fan motor operation by switching A/C ON If 1 and 2 normal, check amount of refrigerant and supply appropriate volume of refrigerant

When there is air in the refrigeration system:

Fig 8: Checking Refrigerant Pressure - Air In Refrigeration System

Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

DIAGNOSTIC NOTE AND MEASUREMENT ITEM / DISPLAY RANGE

Symptoms	Probable Causes	Diagnosis	Corrective Actions
Pressure extremely high on both low and high pressure sides Low pressure piping too hot to touch	Air in refrigeration system	Air in refrigeration system Insufficient vacuum purging	Check whether compressor oil dirty or insufficient Evacuate air and supply new refrigerant

When the expansion valve malfunctions:

Fig 9: Checking Refrigerant Pressure - Expansion Valve Malfunctions

DIAGNOSTIC NOTE AND MEASUREMENT ITEM / DISPLAY RANGE

Symptoms	Probable Causes	Diagnosis	Corrective Actions
Pressure extremely high on both low and high pressure sides Frost or condensation on piping on low pressure side	Expansion valve malfunction	Excessive refrigerant in low pressure piping Expansion valve opening too wide	Replace expansion valve

When the compressor is defective:

Fig 10: Checking Refrigerant Pressure - Compressor Is Defective

DIAGNOSTIC NOTE AND MEASUREMENT ITEM / DISPLAY RANGE

Symptoms	Probable Cause	Diagnosis	Corrective Actions
Pressure extremely high on both low and high pressure sides Pressure extremely low on high pressure side	Internal leakage in compressor	Compression failure of compressor Leakage from damaged valve or broken sliding parts in compressor	Repair or replace compressor

INSPECT IDLING SPEED

Warm up the engine.

Inspect the idling speed when these conditions are established.

Engine warm

Transmission shifted to either the neutral or the parking position.

Standard: for manual transaxle

IDLING SPEED REFERENCE

Condition	Idling Speed
Switch A/C OFF	550 to 650 RPM
Switch A/C ON (A/C Lo → Hi)	700 → 850 RPM

for automatic transaxle

IDLING SPEED REFERENCE

Condition	Idling Speed
Switch A/C OFF	650 to 750 RPM
Switch A/C ON (A/C Lo → Hi)	700 → 850 RPM

If the idling speed is not as specified, check the idle control system.