AC Expansion Valve (TXV)

This procedure covers the removal and replacement of the AC expansion valve (TXV) on a 2022 Rivian EDV 500, including refrigerant recovery, component replacement, and system recharge.

Warnings

Tools required

Parts

• AC Expansion Valve (TXV) × 1 — Use OEM specification
• AC line O-rings kit × 1 — Use OEM specification
• R-1234yf refrigerant × 1 — Per system capacity specification
• PAG oil (AC compressor oil) × 1 — Use OEM specification for EV system

Preparation

1. Park vehicle on level surface and engage parking brake
2. Verify AC system was functioning prior to service to confirm proper diagnosis
3. Open all doors and windows to ensure adequate ventilation
4. Disconnect 12V auxiliary battery negative terminal and wait 2 minutes
5. Confirm high voltage system is not active (vehicle powered down completely)
6. Allow AC system to stabilize to ambient temperature if recently operated
7. Prepare refrigerant recovery machine with clean tank and verify certification

Procedure

1. 1

   Recover refrigerant from AC system
   Connect the R-1234yf recovery machine to the high and low pressure service ports. Follow the recovery machine manufacturer's procedure to fully evacuate all refrigerant from the system. Record the amount of refrigerant and oil recovered. Verify recovery is complete by observing system pressure stabilizes at 0 psi or below for at least 5 minutes.
   ⚠️Never vent refrigerant to atmosphere. Always use certified recovery equipment.
2. 2

   Access expansion valve location
   Remove the front underbody panel or driver side wheel well liner as needed to access the HVAC unit beneath the dashboard area. On the EDV 500, the expansion valve is typically located at the evaporator inlet near the firewall on the passenger side. Remove any protective covers or acoustic insulation blocking access to the HVAC lines.
   ⚠Take care not to damage nearby high voltage cables or connectors during access.
3. 3

   Disconnect electrical connector from expansion valve
   Locate the electrical connector on the TXV body (if equipped with electronic control). Press the locking tab and carefully disconnect the harness connector. Inspect connector terminals for corrosion or damage.
4. 4

   Disconnect refrigerant lines from expansion valve
   Using appropriate line disconnect tools, release the quick-connect fittings or remove the threaded connections at both the inlet and outlet of the expansion valve. Cap all open ports immediately with dust caps or plugs to prevent moisture and contamination entry. Note the orientation of the valve before removal.
   ⚠Some residual refrigerant may escape during disconnection. Wear protective equipment and allow dissipation before proceeding.
5. 5

   Remove mounting hardware
   Remove the bolts or clips securing the expansion valve mounting bracket to the evaporator housing or firewall. Keep all hardware organized for reinstallation.
6. 6

   Remove old expansion valve
   Carefully extract the expansion valve assembly from its mounting location. Inspect the valve body and sensing bulb (if applicable) for signs of damage, contamination, or excessive oil residue that may indicate other system problems. Remove and discard all old O-rings from the refrigerant line connections.
7. 7

   Prepare new expansion valve
   Unpack the new TXV and verify correct part application. Lubricate new O-rings with clean refrigerant oil and install them on the inlet and outlet ports of the new valve. Ensure O-rings are properly seated in their grooves without twisting or damage.
   ℹ️Use only the specified PAG oil type for EV AC systems. Traditional PAG oils may not be compatible.
8. 8

   Install new expansion valve
   Position the new TXV in the mounting location with correct orientation matching the original installation. Ensure any sensing bulb is properly positioned against the evaporator outlet line. Install mounting hardware and secure the bracket.
9. 9

   Reconnect refrigerant lines
   Remove caps from refrigerant line ports. Connect the inlet and outlet refrigerant lines to the new expansion valve, ensuring proper alignment. For quick-connect fittings, push firmly until an audible click confirms engagement. For threaded connections, hand-tighten first, then use torque wrench to proper specification if available. Verify connections are secure.
10. 10

    Reconnect electrical connector
    Plug the electrical harness connector onto the new TXV (if electronically controlled). Ensure the connector locks fully into place with an audible click.
11. 11

    Reinstall access panels
    Reinstall any acoustic insulation, protective covers, wheel well liners, or underbody panels that were removed for access. Ensure all fasteners are secure.
12. 12

    Evacuate AC system
    Connect vacuum pump to the AC service ports. Evacuate the system to at least 29 inches of mercury (inHg) vacuum. Maintain vacuum for a minimum of 30 minutes. After evacuation period, isolate the system and monitor for 10 minutes - vacuum should not drop more than 1 inHg, indicating no major leaks.
    ⚠Proper evacuation is critical to remove all moisture from the system. Inadequate evacuation will lead to system contamination and poor performance.
13. 13

    Recharge AC system
    Using the R-1234yf recharge machine, add the correct amount of refrigerant based on manufacturer specifications (typically found on underhood label). Add the appropriate amount of refrigerant oil if required based on amount lost during recovery. Follow recharge machine procedures to ensure accurate fill.
14. 14

    Perform leak test
    Using an electronic R-1234yf leak detector, check all connections at the expansion valve, service ports, and surrounding areas for any refrigerant leaks. Pay particular attention to the newly installed O-ring connections. If any leaks are detected, recover refrigerant, repair leak, and repeat evacuation and recharge process.
15. 15

    Reconnect battery and test system operation
    Reconnect the 12V auxiliary battery negative terminal. Start the vehicle and allow it to reach ready mode. Turn AC system to maximum cooling with fan on high. Monitor system pressures using manifold gauges - verify pressures are within normal operating range (typically 25-45 psi low side, 150-250 psi high side depending on ambient temperature). Check for proper cooling at cabin vents.

Reassembly

1. Verify all protective panels and covers are reinstalled securely
2. Ensure no tools or parts are left in engine bay or underbody area
3. Clear any diagnostic trouble codes that may have been set during service
4. Update vehicle service records with refrigerant charge amount and date

Verification

• Confirm AC system produces cold air at cabin vents (typically 40-50°F at maximum cooling)
• Verify system pressures remain stable during operation with no unusual fluctuations
• Check that compressor cycles normally without excessive short cycling
• Listen for any abnormal hissing sounds indicating refrigerant leaks
• Verify no warning lights or AC-related fault codes are present
• Re-check all connection points for leaks after 10 minutes of operation using leak detector
• Confirm adequate airflow and no ice formation on evaporator (which would indicate TXV malfunction)

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