Parts for your 2017 Subaru Impreza-Tx valve

2017 Subaru Impreza TX valve: what it is, why it matters, and when to service it

Based on technical sources, the 2017 Subaru Impreza uses a thermal expansion valve (often called a TX valve or TXV) in its factory DENSO air-conditioning system. The Subaru factory service manual for the 2017 Impreza (HVAC and A/C sections) depicts an A/C expansion valve mounted at the evaporator connection, and Subaru genuine parts catalogues list an “A/C expansion valve” for this model. DENSO system documentation for late-model Subarus also shows a TXV-style metering device rather than an orifice tube for the Impreza platform.

On a 2017subaruimpreza, the TX valve regulates how much liquid refrigerant enters the evaporator. It senses outlet temperature and pressure and meters flow so the evaporator runs cold without freezing. That keeps vent temps stable in stop–start traffic and at highway speeds, improves fuel efficiency, and protects the compressor from liquid slugging. If the TXV sticks or clogs, you’ll often see weak or wildly fluctuating cooling, frosty lines at the firewall, hissing, or odd high/low side gauge readings.

As part of normal servicing, the TX valve isn’t a routine replacement item. It’s checked when diagnosing A/C performance complaints, or replaced when the system has been contaminated (for example, after a compressor failure) or shows clear TXV faults. If the A/C circuit is opened on a 2017subaruimpreza, best practice is to replace the O‑rings at the TXV joints, renew the receiver–drier/desiccant pack (on many late Subarus this is integrated in the condenser), and add the correct type and quantity of PAG oil. Always recharge with the refrigerant type and charge mass printed on the under‑bonnet label (markets vary between R‑134a and R‑1234yf).

• Have a licensed A/C technician (ARCtick in AU/NZ) recover refrigerant, depressurise the system, and perform the work safely.
• The TXV on the Impreza is fitted at the evaporator connections, access varies by trim and may involve working at the firewall/engine bay and/or the HVAC case.
• After reassembly, pressure‑test with dry nitrogen, vacuum to deep level, confirm it holds vacuum, then recharge to spec and verify superheat/subcooling and vent temps.
• If metal debris is present, insist on line flushing, condenser replacement (if it’s the micro‑tube type), and TXV replacement to avoid repeat failures.

A bit of preventive care goes a long way: keep the condenser face clean, replace the cabin filter on schedule, run the A/C regularly to circulate oil, and address any cooling drop‑off early before it snowballs into compressor damage. Treated right, the 2017subaruimpreza TX valve quietly does its job for years.

Does the 2017 Subaru Impreza actually have a TX valve?

Yes. Subaru’s own service documentation and parts listings identify an A/C expansion (TX) valve on the 2017 Impreza’s DENSO HVAC system, fitted at the evaporator connection.

It’s the metering device that balances refrigerant flow so the evaporator stays cold without icing, delivering consistent cabin temps.

What symptoms point to a failing TX valve on a 2017subaruimpreza?

Common signs include weak or inconsistent cooling, evaporator/freightline frosting near the firewall, audible hissing or whooshing, and abnormal gauge pressures (starved low side with high superheat, or flooding/low superheat).

After compressor failure or debris in the lines, the TXV can clog or stick and should be replaced along with other contaminated components.

Should the TX valve be replaced as regular maintenance?

No, it’s not a scheduled item. Replace it when there’s confirmed TXV malfunction, contamination, or whenever the system’s opened and evidence suggests metering issues.

Always have a licensed A/C pro recover refrigerant, fit new O‑rings, renew the drier/desiccant, vacuum and recharge to the exact spec on the car’s label.