Rear Expansion Valve

Rear Expansion Valve

• After the A/C compressor is switched off in this vehicle, it may take a relatively long time for the pressure on the high pressure side to decrease (the expansion valve(s) is/are cold, the pressure on the low pressure side increases quickly after deactivation, the expansion valve(s) closes/close and the refrigerant can only flow slowly to the low pressure side).

• There are different versions of the expansion valve (and thus different refrigerant lines to the expansion valve) depending on the production period. Therefore, ensure proper allocation using the Electronic Parts Catalog.

Removing

- Switch off the ignition.

- Drain the refrigerant circuit.

- Remove the left aerodynamic underbody trim.

- Remove the refrigerant lines from the rear expansion valve, refer to => [ Rear Expansion Valve Refrigerant Lines, Disconnecting ] Rear Expansion Valve Refrigerant Lines, Disconnecting.

- Remove the screws - A -.






- Remove expansion valve - B - from refrigerant lines - C - and - D - (to the evaporator in the rear A/C unit).

• Seal all open lines and connections on the expansion valve with suitable caps (to protect against damage and to keep dirt and moisture from entering the system).

Installing

Installation is carried out in the reverse order while noting the following:

- Clean refrigerant line connections on expansion valve - B - and on refrigerant lines - C - and - D -, and check for damage.

- Replace O-ring seals - F - and - G -; refer to the Electronic Parts Catalog.

- Coat O-ring seals - F - and - G - with refrigerant oil before installation. Refer to => [ Refrigerant Circuit O-rings ] Refrigerant Circuit O-rings.

- Ensure that O-ring seals - F - and - G - are properly seated on the connections of refrigerant lines - C - and - D - to the evaporator.

- Ensure that retaining plate - E - is seated properly on refrigerant lines - C - and - D -.

• Expansion valve is available in different versions (same housing but a different control characteristic), therefore ensure the exact allocation using Electronic Parts Catalog.

• Coat the O-ring with refrigerant oil before installing. Refer to => [ Refrigerant Circuit O-rings ] Refrigerant Circuit O-rings.

• Retaining plate - G - is attached to refrigerant lines - C - and - D -. Ensure proper seating when installing expansion valve - B -.

- Place expansion valve - B - on the connections of refrigerant lines - C - and - D -.

- Insert and tighten bolts - A -.

• Tightening torque of bolts - A - with a thread "M6" 10 Nm.

- Install the refrigerant lines to the rear expansion valve. Refer to => [ Rear Expansion Valve Refrigerant Lines, Disconnecting ] Rear Expansion Valve Refrigerant Lines, Disconnecting.

- Check the routing of the refrigerant lines after attachment. They must be inserted in the provided brackets in a tension-free manner and must not come in contact with other components.

- Evacuate and fill the refrigerant circuit.

- Install the remaining removed components.

- Check the event memory of the Climatronic control module (J255) , and erase any displayed malfunctions using the Vehicle Diagnostic Tester in the "Guided Fault Finding" function.

- Operate the A/C system after filling the refrigerant circuit, refer to => [ A/C System Operating After Filling Refrigerant Circuit ] A/C System Operating After Filling Refrigerant Circuit.

• Note the information regarding operation of the A/C system after filling.

• Check the function of the A/C system using the Vehicle Diagnostic Tester in the "Guided Fault Finding" function.