This procedure covers the replacement of the AC expansion valve (TXV) on a 2014-2019 Toyota Corolla with a 1.8L I4 engine, requiring AC system evacuation and recharge.

Warnings

Tools required

Parts

• AC Expansion Valve (TXV) × 1 — Use OEM Toyota part number for 1.8L model
• AC line O-rings (various sizes) × 4 — Use OEM specification
• PAG oil for AC system × 1 — ND-11 PAG oil
• R-134a refrigerant × 1 — Approximately 18-22 oz total system capacity

Preparation

1. Ensure engine is completely cool before beginning work
2. Park vehicle on level surface and engage parking brake
3. Disconnect negative battery terminal and wait 3 minutes for airbag system discharge
4. Recover AC refrigerant using EPA-approved recovery machine and document amount recovered
5. Remove engine cover by pulling upward on clips
6. Take photos of AC line routing for reference during reinstallation

Procedure

1. 1

   Access evaporator and expansion valve
   Remove the glove box by opening fully, squeezing sides inward to release stoppers, and lowering down. Remove lower dashboard panel on passenger side by removing plastic clips and screws. Locate the evaporator housing behind the blower motor assembly.
2. 2

   Disconnect AC lines from expansion valve
   Using flare nut wrenches, carefully loosen the liquid line and suction line connections at the expansion valve inlet and outlet. The expansion valve is typically mounted at the evaporator inlet. Support the evaporator housing while loosening to prevent stress on mounting points. Cap or plug open lines immediately to prevent moisture entry.
   ⚠Use two wrenches (one to hold, one to turn) to prevent twisting AC lines. Damaged lines require replacement.
   Torque spec

   AC Line Fittings20 Nm (15 lb-ft)
3. 3

   Remove expansion valve cover
   Remove the cover or access panel from the evaporator housing to expose the expansion valve. This typically requires removing several small screws around the perimeter. Keep track of screw locations as they may be different lengths.
   Torque spec

   Cover Screws10 Nm (8 lb-ft)
4. 4

   Remove expansion valve mounting
   Remove the mounting bolts or clips securing the expansion valve to the evaporator. The valve body will be held by 2-3 small bolts. Note the orientation of the sensing bulb (if equipped) and its routing before removal.
   Torque spec

   Expansion Valve10 Nm (7 lb-ft)
5. 5

   Extract old expansion valve
   Carefully pull the expansion valve from the evaporator inlet tube. Remove and discard all old O-rings from the valve seats and AC line connections. Inspect the evaporator inlet tube for damage, debris, or signs of contamination. Clean mating surfaces with lint-free shop towels.
   ℹ️If metal debris or discoloration is present, flush the AC system before installing new valve to prevent premature failure.
6. 6

   Prepare new expansion valve
   Unpack new expansion valve and verify correct part number matches vehicle application. Lubricate all new O-rings with fresh PAG ND-11 oil. Install new O-rings onto the expansion valve body, ensuring they seat properly in their grooves without twisting.
7. 7

   Install new expansion valve
   Carefully insert the new expansion valve into the evaporator inlet tube, ensuring O-rings do not roll or pinch. Align mounting holes and hand-thread mounting bolts. Torque mounting bolts to specification in a cross-pattern if multiple bolts are present.
   ⚠Do not overtighten small bolts on evaporator housing as the plastic housing can crack.
   Torque spec

   Expansion Valve10 Nm (7 lb-ft)
8. 8

   Reinstall evaporator cover
   Position the expansion valve sensing bulb (if equipped) according to original routing. Reinstall the evaporator housing cover, ensuring gasket or seal is properly positioned. Install and torque cover screws evenly.
   Torque spec

   Cover Screws10 Nm (8 lb-ft)
9. 9

   Reconnect AC lines
   Install new O-rings on both AC line fittings and lubricate with PAG oil. Connect liquid line and suction line to expansion valve, hand-threading fittings first to ensure proper engagement. Using flare nut wrenches, torque AC line fittings to specification. Add specified amount of PAG oil through the suction line (typically 1-2 oz for valve replacement).
   ⚠Cross-threading aluminum AC fittings will require expensive line replacement. Hand-thread carefully before using wrenches.
   Torque spec

   AC Line Fittings20 Nm (15 lb-ft)
10. 10

    Evacuate AC system
    Connect AC service equipment to high and low side service ports. Evacuate system to 29+ inches of vacuum for minimum 30 minutes. Monitor for vacuum decay which indicates a leak. If vacuum holds steady for 10 minutes after pump shutoff, system is sealed properly.
    ⚠If system will not hold vacuum, locate and repair leak before charging. Charging a leaking system wastes refrigerant and damages environment.
11. 11

    Recharge AC system
    Charge AC system with R-134a refrigerant to the amount specified on underhood label (typically 18-22 oz for 1.8L Corolla). Use charging equipment to measure exact quantity. Do not overcharge as this reduces cooling efficiency and can damage compressor.
12. 12

    Reinstall interior panels
    Reinstall lower dashboard panel and glove box in reverse order of removal. Ensure all clips and fasteners are secure. Reconnect negative battery terminal.

Reassembly

1. Verify all AC line connections are tight and show no signs of oil seepage
2. Ensure interior panels are fully secured with no loose clips or rattles
3. Reinstall engine cover by pressing down on mounting clips until seated

Verification

• Start engine and turn AC to maximum cold with fan on high
• Allow system to run for 5 minutes, then check that both AC lines at firewall are cold to touch (suction line should be coldest)
• Verify center dashboard vent temperature reaches 38-45°F within 10 minutes with ambient temperature above 70°F
• Check for refrigerant leaks using electronic leak detector or soap solution at all connections
• Verify compressor cycles on and off normally without unusual noises
• Confirm no moisture or frost accumulation on AC lines indicating restriction
• Test system at idle and at 2000 RPM to verify consistent cooling performance

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