Purpose
The expansion valve atomizes liquid refrigerant to facilitate cooling of the evaporator.
Function
The expansion valve reduces the pressure of liquid refrigerant rapidly to facilitate vaporization of the atomized refrigerant at the evaporator, and adjusts the refrigerant amount sent into the evaporator.
Construction
The expansion valve consists of the following parts:
Diaphragm
Temperature sensor
Shaft
Expansion valve body
Ball valve
Spring

Operation
Adjustment of the refrigerant amount supplied to the evaporator is performed by the ball valve opening angle in the expansion valve.
The opening angle adjustment is performed according to the balance of the following forces:

Refrigerant pressure (Pd) in diaphragm
Refrigerant gas pressure (PI) of evaporator under diaphragm
Spring force (Fs) pushing up ball valve
If the refrigerant gas temperature from the evaporator increases, the expansion valve increases the amount of refrigerant according to the following operations:

The temperature of the temperature sensor tightly sealed against the diaphragm increases.
The refrigerant in the diaphragm warms and the Pd increases.
If this Pd increases more than PI + Fs, the diaphragm is pressed down.
The shaft installed to the temperature sensor end presses down the ball valve.
The amount of refrigerant is increased.
If the refrigerant gas temperature from the evaporator decreases, the expansion valve decreases the amount of refrigerant flow according to the following operation:

The temperature of the temperature sensor tightly sealed against the diaphragm decreases.
The refrigerant temperature in the diaphragm decreases and the Pd decreases.
The Pd decreases less than PI + Fs.
The ball valve installed to the temperature sensor end is pressed up.
The amount of refrigerant is decreased.
Fail-safe
Function not equipped.
Evaporator Inspection
Expansion Valve Removal/InstallationVanity Mirror Illumination Bulb Removal/Installation
1. Disconnect the negative battery cable..
2. Insert a tape-wrapped flathead screwdriver into the service hole in the position
shown in the figure.
3. Move a flathead screwdriver in the direction of the arrow (1) shown in the
figure and detach the lens tab and sunvisor.
4. Detach a ...
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1. Perform the KOEO self-test..
2. Verify that a fuel pump control module related DTC is detected..
If DTCs are detected, repair the malfunctioning part according to the applicable
DTC troubleshooting..
If a DTC is not detected, go to the next step.
3. Inspect the followin ...
Power Brake Unit Inspection
NOTE:
The following inspection methods are simple inspection methods to judge the
function of the power brake unit.
If there is any malfunction in the power brake unit, replace the power brake
unit as a single unit.
Without Using SST
Operation inspection
1. With the eng ...