AC Expansion Valve (TXV)

Replace the AC expansion valve (TXV) on a 2016-2021 Honda Civic 1.5L turbo, requiring AC system evacuation, refrigerant recovery, and recharge.

Warnings

Tools required

Parts

• AC Expansion Valve (TXV) × 1 — Use OEM Honda part number 80221-TGG-A01 or equivalent
• AC O-ring kit (various sizes) × 1 — Use OEM specification
• R-134a refrigerant × 1 — Typically 14-16 oz total system capacity
• PAG 46 compressor oil × 1 — Use Honda-approved PAG 46

Preparation

1. Ensure vehicle is parked on level ground with parking brake engaged
2. Allow engine and AC system to cool completely (minimum 1 hour after operation)
3. Verify you have EPA 609 certification and proper AC recovery equipment
4. Gather all replacement parts and verify correct expansion valve part number for your specific model year
5. Have new O-rings and PAG 46 oil ready before breaking any refrigerant connections

Procedure

1. 1

   Recover refrigerant from AC system
   Connect AC recovery machine to both high and low side service ports. Follow machine instructions to completely recover all refrigerant from the system. Record the amount of refrigerant and oil recovered for recharge reference. Ensure recovery is complete before proceeding.
   ⚠️Never skip refrigerant recovery. Venting refrigerant is illegal and environmentally harmful.
2. 2

   Disconnect battery negative terminal
   Disconnect the negative battery terminal and wait 3 minutes to allow airbag system to discharge. This prevents accidental fan operation and electrical issues during the repair.
3. 3

   Remove engine cover and air intake components
   Remove the plastic engine cover by pulling upward on the retaining clips. Loosen the clamp on the air intake tube at the throttle body and remove the air intake duct to improve access to the AC lines. On some models, you may need to remove the entire air box assembly.
4. 4

   Access expansion valve location
   The expansion valve is located on the evaporator inlet line near the firewall on the passenger side. You may need to remove plastic covers or move wiring harnesses aside for clear access. The valve is typically mounted where the liquid line enters the evaporator.
5. 5

   Disconnect liquid line from expansion valve
   Using a flare nut wrench to prevent rounding, carefully loosen and disconnect the liquid line fitting from the inlet side of the expansion valve. Immediately cap or plug both the line and valve port to prevent moisture and debris entry. Remove and discard the old O-ring.
   ⚠Use flare nut wrenches only - regular wrenches will round off the soft aluminum fittings.
6. 6

   Disconnect evaporator line from expansion valve
   Disconnect the evaporator inlet line from the outlet side of the expansion valve using a flare nut wrench. Cap or plug both openings immediately. Remove and discard the old O-ring. Note the orientation of the expansion valve for proper installation of the new valve.
7. 7

   Remove expansion valve mounting
   Remove the mounting bolt or bracket securing the expansion valve to its mounting location. On this model, the valve may be held by a single mounting bolt or integrated into a bracket. Carefully remove the old expansion valve and any associated mounting hardware.
8. 8

   Prepare new expansion valve
   Unpack the new expansion valve and verify it matches the old unit exactly. Coat the new O-rings with a thin layer of PAG 46 oil. Install new O-rings onto both ports of the new expansion valve. Add approximately 1-2cc of fresh PAG 46 oil into the inlet port of the new valve to replace oil lost during recovery.
   ⚠Do not remove new expansion valve from packaging until ready to install. Minimize exposure to atmospheric moisture.
9. 9

   Install new expansion valve
   Position the new expansion valve in the correct orientation (inlet toward liquid line, outlet toward evaporator). Install the mounting bolt or bracket and torque to specification. Ensure the valve is securely mounted and properly aligned with both refrigerant lines.
   Torque spec

   Expansion Valve10 Nm (7 lb-ft)
10. 10

    Connect evaporator line to expansion valve
    Remove the cap from the evaporator line and expansion valve outlet port. Install a new O-ring onto the evaporator line fitting with a thin coat of PAG 46 oil. Hand-thread the fitting carefully to avoid cross-threading, then torque to specification using a flare nut wrench.
    ⚠Always start fittings by hand to ensure proper thread engagement before using tools.
    Torque spec

    AC Line Fittings20 Nm (15 lb-ft)
11. 11

    Connect liquid line to expansion valve
    Remove the cap from the liquid line and expansion valve inlet port. Install a new O-ring onto the liquid line fitting with a thin coat of PAG 46 oil. Hand-thread the fitting carefully, then torque to specification using a flare nut wrench.
    Torque spec

    AC Line Fittings20 Nm (15 lb-ft)
12. 12

    Reinstall removed components
    Reinstall the air intake components, air box assembly if removed, and engine cover. Ensure all clips and fasteners are properly secured. Reconnect the negative battery terminal.
13. 13

    Evacuate AC system
    Connect the AC evacuation equipment to the service ports. Evacuate the system to a deep vacuum (minimum 500 microns, ideally below 300 microns) for at least 30-45 minutes. Monitor with a digital vacuum gauge. A proper vacuum removes all moisture and air from the system.
    ⚠Insufficient evacuation will leave moisture in the system, causing corrosion and poor performance.
14. 14

    Perform vacuum hold test
    After evacuation, close all valves and monitor vacuum for 10-15 minutes. Vacuum should hold steady with minimal rise (less than 100 microns). A significant vacuum loss indicates a leak that must be found and corrected before charging.
15. 15

    Recharge AC system
    Using the AC machine, recharge the system with the amount of R-134a recovered (or factory specification of approximately 14-16 oz for this model). Add the appropriate amount of PAG 46 oil if not already added during valve installation. Follow machine instructions for proper charging procedure.

Reassembly

1. Verify all AC line fittings are torqued to specification and have new O-rings installed
2. Confirm all engine covers, air intake components, and trim panels are properly reinstalled
3. Ensure battery is reconnected and all electrical connectors are secured
4. Double-check that no tools or parts are left in the engine compartment

Verification

• Start the engine and turn AC to maximum cold with fan on high
• Allow system to run for 5-10 minutes and verify cold air output from vents (should reach 40-50°F)
• Monitor AC pressures: Low side should be 25-35 PSI, high side should be 200-250 PSI at idle with ambient temp around 80°F
• Use refrigerant leak detector to check all connections made during repair for leaks
• Verify compressor clutch engages and disengages properly
• Check that condenser fans operate when AC is on
• Listen for unusual noises from AC system during operation
• Confirm no visible oil residue around fittings after 24 hours of operation

More procedures for this vehicle