Parts for your 2021 Mitsubishi Asx-Tx valve

2021 Mitsubishi ASX TX Valve: What It Does and How to Look After It

Technical sources confirm the 2021 Mitsubishi ASX uses a thermostatic expansion valve (TXV), not an orifice tube. The Mitsubishi Motors Service Manual for RVR/ASX (2019–2022, Group 55A Heating and Air Conditioning), along with Mitsubishi’s ASA electronic parts catalogue listings for the ASX HVAC evaporator assembly, specify an “expansion valve” at the evaporator inlet. DENSO’s OEM A/C architecture for the ASX/RVR platform also shows a TXV-type system. So yes—this model is fitted with a TX valve.

The TX valve meters liquid refrigerant into the evaporator based on superheat, keeping the coil cold without flooding it. That balance delivers steady vent temps, protects the compressor from liquid slugging, and adapts to changes in cabin load—like a hot car after work or a cool evening run. It’s a small part that quietly does a big job in the ASX’s comfort game.

While the TXV isn’t a scheduled service item, it benefits from clean, dry refrigerant and a system that’s free of debris. When it sticks or clogs, you’ll often feel it long before you see it.

• Common signs: weak or icy-cold cycling A/C, frosty or sweating lines at the firewall, hissy or chattery operation, erratic high/low gauge pressures, or poor cooling at idle but better on the move.
• Likely causes: moisture in the system, debris after a compressor event, incorrect oil balance, or internal wear.

If the TX valve needs replacing on a 2021 ASX, expect dash-area access to the evaporator—labour can be the bigger part of the bill. Best practice in Australia and New Zealand is to have a licensed A/C technician handle it (ARCtick in AU, appropriate refrigerant licence in NZ). When opening the system, they should:

• Recover refrigerant and cap lines to keep moisture out.
• Replace the TXV and all related O-rings, lightly oiling new seals with the correct PAG oil.
• Fit a new receiver-drier/desiccant pack whenever the system is opened.
• Evacuate (vacuum) thoroughly, leak-test, then recharge by weight to the under-bonnet label spec (ASX variants may use R-134a or R-1234yf depending on market—always check the label).
• After any compressor failure, flush lines and condenser (or replace if non-flushable), then confirm correct oil balancing.

For happy long-term running, keep the cabin filter fresh, the condenser face clean of bugs and fluff, and book an annual A/C performance check. Skip sealant “quick fixes”—they can foul a TXV and cost more later.

Does the 2021 Mitsubishi ASX have a TX valve or an orifice tube?
It’s a TX valve setup. Mitsubishi’s service documentation for the RVR/ASX platform (2019–2022) and the OEM parts catalogue call out an expansion valve mounted at the evaporator. That design suits variable loads and helps stabilise vent temps better than a fixed orifice in this vehicle.

What are the symptoms of a failing TX valve on an ASX?
Owners usually report inconsistent cooling, frosty or sweating lines near the firewall, and pressure readings that don’t make sense on gauges. Cooling might be weak at idle then improve with revs, or blow cold then warm in cycles. Any of these are a cue to have a licensed tech test the system.

How much does TX valve replacement cost in AU/NZ?
Parts are typically modest, but labour can add up because of access to the evaporator area. Ballpark figures often land between $600 and $1,200 AUD/NZD including re-gas and a new drier, but it varies by workshop, refrigerant type, and whether extra work (like flushing after a compressor failure) is needed.