Last Modified: 04-05-2023 |
6.11:8.1.0 |
Doc ID: RM100000000VK1U |
Model Year Start: 2016 |
Model: Sienna |
Prod Date Range: [12/2015 -
] |
Title: HEATING / AIR CONDITIONING: REFRIGERANT: ON-VEHICLE INSPECTION; 2016 - 2020 MY Sienna [12/2015 - ] |
ON-VEHICLE INSPECTION
PROCEDURE
1. CHECK REFRIGERANT PRESSURE USING MANIFOLD GAUGE SET
(a) 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 is on.
-
Blower speed control switch at HI.
-
Engine running at 1500 rpm.
-
Air inlet mode damper set at RECIRC.
-
Temperature control switch in MAX. COLD position.
-
Air temperature at air inlet 30 to 35°C (86 to 95°F).
(1) When the refrigerant volume is correct, the gauge reading indicates as follows:
Gauge Reading:
Pressure Side
|
Specified Condition
|
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:
Pressure varies in accordance with certain conditions (outside air temperature, sunlight and wind).
|
|
(2) When there is moisture in the refrigeration system:
Symptom
|
Probable Cause
|
Diagnosis
|
Corrective Action
|
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
-
Charge appropriate volume of new refrigerant
|
(3) When cooling is insufficient:
Symptom
|
Probable Cause
|
Diagnosis
|
Corrective Action
|
-
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 halogen leak detector, and repair if necessary
-
Charge 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
|
(4) When the circulation of the refrigerant is poor:
Symptom
|
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
|
(5) When the refrigerant does not circulate:
Symptom
|
Probable Cause
|
Diagnosis
|
Corrective Action
|
-
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 charge appropriate volume of new refrigerant
-
For gas leakage from expansion valve, replace expansion valve
|
(6) When the refrigerant is overcharged or cooling of condenser is insufficient:
Symptom
|
Probable Cause
|
Diagnosis
|
Corrective Action
|
-
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 charge appropriate volume of refrigerant
|
(7) When there is air in the refrigeration system:
Symptom
|
Probable Cause
|
Diagnosis
|
Corrective Action
|
-
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 charge new refrigerant
|
(8) When the expansion valve malfunctions:
Symptom
|
Probable Cause
|
Diagnosis
|
Corrective Action
|
-
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
|
(9) When the compressor is defective:
Symptom
|
Probable Cause
|
Diagnosis
|
Corrective Action
|
-
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
|
2. INSPECT IDLING SPEED
(a) Warm up the engine.
(b) Inspect idling speed when these conditions are established.
-
Check the idle speed with the cooling fans off.
-
Turn off all the electrical systems.
-
When checking the idle speed, the transaxle should be in neutral or park.
Standard:
Condition
|
Idling Speed
|
A/C switch is off
|
600 to 700 rpm
|
A/C switch is on (A/C Lo → Hi)
|
650 → 800 rpm
|
If the idling speed is not as specified, check the idle control system.
|