AC Expansion Valve (TXV)

This procedure covers the removal and replacement of the AC expansion valve (TXV) on the 2024 Rivian EDV 500, including refrigerant recovery, component removal, and system recharge.

Warnings

Tools required

Parts

• AC Expansion Valve (TXV) × 1 — Use OEM specification
• TXV O-rings and seals kit × 1 — Use OEM specification
• PAG oil for R-1234yf systems × 1 — Use OEM specification
• R-1234yf refrigerant × 1 — As needed to refill system

Preparation

1. Park vehicle on level surface and engage parking brake
2. Ensure high-voltage battery is in service mode following Rivian HV safety procedures
3. Verify AC system is off and has cooled to ambient temperature
4. Connect R-1234yf recovery machine and verify proper operation
5. Document refrigerant charge amount during recovery for refill reference
6. Remove driver-side front wheel
7. Remove driver-side front wheel well liner (partial removal)

Procedure

1. 1

   Recover refrigerant from AC system
   Connect the R-1234yf recovery machine to the low and high-side service ports. Follow machine instructions to fully recover all refrigerant from the system. Record the amount recovered for later reference. Verify system shows zero pressure on gauges before proceeding.
   ⚠️Never open refrigerant lines under pressure. Ensure complete recovery before disconnecting any components.
2. 2

   Access TXV mounting location
   Open the frunk and remove the driver-side trim panels to access the HVAC module area. From underneath, access the TXV through the wheel well opening. The TXV is mounted on the evaporator inlet, located near the firewall behind the motor compartment insulation. Remove any electrical harness clips or brackets obstructing access.
   ⚠Be careful not to damage high-voltage cables or connectors near the HVAC module area.
3. 3

   Disconnect TXV electrical connector
   Locate the TXV temperature sensor connector on the valve body. Press the locking tab and carefully disconnect the electrical connector. Move the harness aside and secure it away from the work area.
4. 4

   Disconnect refrigerant lines from TXV
   Using the appropriate refrigerant line disconnect tools, carefully separate the inlet and outlet refrigerant lines from the TXV. Cap or plug all open refrigerant ports immediately to prevent moisture and contaminant entry. Inspect the line fittings for damage or corrosion.
   ⚠Residual refrigerant or oil may escape when disconnecting lines. Ensure adequate ventilation and wear eye protection.
5. 5

   Remove TXV mounting hardware
   Remove the mounting bolts or clips securing the TXV to the evaporator housing. On the EDV 500, this typically consists of two mounting bolts accessible from the wheel well side. Support the TXV while removing the final fastener.
6. 6

   Remove old TXV
   Carefully extract the TXV from its mounting position. Note the orientation and position of the sensing bulb if equipped. Remove and discard all old O-rings and seals from the TXV ports and mating surfaces.
7. 7

   Prepare new TXV for installation
   Unpack the new TXV and verify part number matches application. Lubricate all new O-rings with the appropriate PAG oil for R-1234yf systems. Install new O-rings onto the TXV ports. Add the manufacturer-specified amount of PAG oil to the TXV (typically 1-2 oz unless pre-charged).
   ℹ️Only use PAG oil compatible with R-1234yf refrigerant. Using incorrect oil can damage the AC system.
8. 8

   Install new TXV
   Position the new TXV in the mounting location, ensuring correct orientation. If equipped with a sensing bulb, route it to the proper location on the evaporator outlet. Install mounting bolts and tighten evenly. Without specific torque values, tighten bolts snugly to prevent refrigerant leaks while avoiding overtightening aluminum components.
9. 9

   Connect refrigerant lines
   Remove caps from refrigerant lines and TXV ports. Inspect O-rings one final time. Connect the inlet and outlet refrigerant lines to the TXV, ensuring each connection clicks or seats fully. Verify connections are secure by attempting to pull lines apart gently.
10. 10

    Reconnect electrical connector
    Reconnect the TXV temperature sensor electrical connector. Ensure the connector locks fully into place with an audible click. Verify the harness routing does not interfere with any moving parts or sharp edges.
11. 11

    Evacuate AC system
    Connect the vacuum pump to the AC system service ports. Evacuate the system to at least 29 inches of mercury (500 microns or better). Hold vacuum for minimum 30 minutes to verify system integrity and remove all moisture. If vacuum does not hold, locate and repair the leak before proceeding.
    ⚠Inadequate evacuation will leave moisture in the system, causing corrosion and poor AC performance.
12. 12

    Recharge AC system
    Using the R-1234yf recharge machine, add refrigerant to the system according to the amount recovered earlier or the specification on the underhood label. Monitor pressures during charging. Add UV dye if desired for future leak detection. Verify charge level matches specifications.
13. 13

    Leak test system
    With the system charged, use an electronic R-1234yf leak detector to check all connections at the TXV, refrigerant lines, and surrounding areas. If UV dye was added, use a UV lamp to inspect for leaks. Address any leaks found before proceeding.

Reassembly

1. Reinstall any electrical harness clips or brackets that were removed for access
2. Reinstall HVAC module insulation and frunk trim panels
3. Reinstall driver-side wheel well liner and secure all fasteners
4. Reinstall driver-side front wheel and torque lug nuts to specification
5. Clear high-voltage service mode and restore vehicle to normal operation

Verification

• Start the vehicle and enable the AC system at maximum cooling
• Verify the AC compressor engages and runs smoothly without unusual noises
• Check that cold air is produced at the vents within 2-3 minutes
• Monitor AC pressures: low-side should be 25-45 PSI and high-side 150-250 PSI at idle (ambient dependent)
• Verify no refrigerant odor or visible leaks around TXV connections
• Confirm TXV temperature sensor is reading properly with a scan tool (no DTCs)
• Test AC performance in various modes and fan speeds to ensure proper operation
• Perform a final leak check with electronic detector after system has operated for 10 minutes

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