Parts for your 2015 Mitsubishi Asx-Tx valve

2015 Mitsubishi ASX TX Valve: what it does and when to replace it

Based on technical sources — including the Mitsubishi ASX/Outlander Sport (RVR) factory workshop manual A/C section, the Mitsubishi ASA parts catalogue diagrams, and DENSO/aftermarket parts catalogues that list an A/C expansion valve for this model — the 2015 Mitsubishi ASX uses a thermostatic expansion valve (TX valve) mounted at the evaporator. It’s not an orifice-tube system on this vehicle.

The TX valve’s job is to meter the flow of refrigerant into the evaporator, reacting to temperature and pressure so the core stays cold without icing up. By controlling superheat, it keeps cabin temps steady, improves pull-down on hot days, and helps the compressor work efficiently. In short, it’s the brains of the air-con metering side, matching refrigerant flow to heat load so passengers stay comfy from school run to road trip.

While the TX valve isn’t a routine service item, age, moisture ingress, or debris after a compressor issue can make it stick or clog. Common clues include weak cooling at idle or cruise, vent temps that swing hot–cold, frosting at the evaporator or lines, and odd pressure readings during gauge tests. A proper diagnosis with manifold gauges and temperature probes beats guesswork every time.

• Only replace the TX valve when testing points to a fault. It’s tucked at the evaporator, so access typically involves glovebox and HVAC case work — allow time for dash-side labour.
• Anytime the system is opened, fit a new receiver–drier/desiccant (often integrated with the condenser on late-model ASX) and new O-rings lightly lubricated with the correct compressor oil type specified for the ASX. Keep everything squeaky clean to avoid introducing grit.
• After reassembly, evacuate with a good vacuum, then recharge to the exact R134a fill shown on the under-bonnet label. Correct charge is critical to TX valve behaviour.
• Torque fittings to spec, don’t over-tighten the flare/block connections at the valve.
• If the compressor has failed, flush appropriate lines and replace the condenser if it uses a parallel-flow design that can’t be reliably flushed.
• Keep the cabin filter fresh and run the air-con regularly year-round — it circulates oil and keeps seals happy.
• In Australia and New Zealand, refrigerant handling must be carried out by a licensed technician. It’s safer, legal, and protects the system from costly rework.

With the right diagnosis and care at replacement, the ASX’s TX valve will deliver crisp, reliable cooling through the hottest summers.

FAQs

Does the 2015 Mitsubishi ASX use a TX valve or an orifice tube?
Technical references — the Mitsubishi service manual A/C section, OEM parts catalogues, and DENSO/aftermarket listings — show the 2015 ASX uses a thermostatic expansion valve at the evaporator, not an orifice tube.

How often should the TX valve be replaced?
It isn’t a scheduled maintenance item. Replace it only if testing confirms it’s sticking, blocked, or leaking. When replacing, also renew the receiver–drier/desiccant and O-rings, evacuate properly, and recharge to the exact R134a spec.

What are signs of a blocked or faulty TX valve on an ASX?
Warm air at the vents, temperature swings, icing on the evaporator or lines, hissing at the firewall, and abnormal gauge readings (low-side too low or erratic) are common signs. Have a licensed A/C tech confirm with proper diagnostics.