Scheme 36
Scheme 36: ON-VEHICLE INSPECTION
Scheme 37
Scheme 38
Scheme 39
Scheme 40
Scheme 41
Scheme 42
Scheme 43
Scheme 44
Scheme 45
- 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. Item Symptom Amount of Refrigerant Corrective Procedures 1 Bubbles visible Insufficient* (1) Check for gas leakage and repair if necessary (2) 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 (1) Check for gas leakage with gas leak detector and repair if necessary (2) 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 (1) Drain or discharge refrigerant (2) 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 RECIRC. 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: Gauge reading Pressure side Refrigerant volume Low 0.15 to 0.25 MPa (1.5 to 2.5 kgf/cm 2 , 22 to 36 psi) High 1.37 to 1.57 MPa (14 to 16 kgf/cm 2 , 199 to 228 psi) HINT: Pressure varies in accordance with certain conditions (outside air temperature, sunlight and wind). When there is moisture in the refrigeration system: 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: Symptoms Probable Cause Diagnosis Corrective Actions Pressure low on both low and high pressure sides Bubbles are seen through sight glass continuously 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: 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: 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: Symptoms Probable Causes Diagnosis Corrective Actions Pressure extremely high on both sides No air bubbles are seen through sight glass even when engine RPM lowers 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: Symptoms Probable Causes Diagnosis Corrective Actions Pressure extremely high on both low and high pressure sides Low pressure piping too hot to touch Bubbles can be seen through sight glass 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: 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: 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 idling speed when these conditions are established. Standard for 2ZR-FE manual transaxle for 2ZR-FE automatic transaxle Condition Idling Speed Switch A/C OFF 650 to 750 RPM Switch A/C ON (A/C Lo --> Hi) 750 --> 850 RPM 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.
