Parts for your 2009 Subaru Impreza-Tx valve

2009 Subaru Impreza TX Valve: What it does, where it is, and when to replace it

Technical sources confirm the 2009 Subaru Impreza is fitted with a thermostatic expansion valve (TX valve/TXV) as part of its factory air‑conditioning system. References include the Subaru Service Manual for the 2009 Impreza (HVAC section), the Subaru Electronic Parts Catalogue listing “Valve – Expansion” for 2008–2011 Impreza models (e.g., P/N 73520FG000), and DENSO air‑conditioning system fundamentals describing TXV‑type systems used in many Subaru applications. So yes—on a 2009 Impreza, the TX valve is both relevant and used.

In this Subaru, the TXV meters refrigerant into the evaporator based on outlet temperature and pressure, keeping the evaporator cold without freezing. That smart metering is why vents stay frosty at cruise yet don’t ice up when idling at the lights. When a TXV starts sticking or mis‑metering, owners may notice warm air at idle, wildly fluctuating vent temps, hissing, occasional evaporator icing, or odd high/low gauge readings during a regas check.

While the TX valve isn’t a routine service item like a cabin filter, it benefits from good system hygiene. Keeping the condenser clean, the drive belt healthy, and the cabin filter fresh helps the TXV do its job. Because refrigerant handling is regulated in AU/NZ, any TXV diagnosis or replacement should be left to a licensed air‑con technician (ARCtick/NZ‑certified).

• Typical replacement steps a pro will follow:
  1. Recover refrigerant legally, then access the valve at the evaporator area (passenger side, glovebox/trim removal is common).
  2. Replace the TXV and all related O‑rings, lightly lubricated with the correct PAG oil.
  3. Leak‑test, deep vacuum, and recharge R‑134a by weight to the sticker under the bonnet.
  4. Verify operation with pressure readings, vent temps, and check for proper superheat/subcool.

If the system has seen compressor wear (metallic debris/“black death”), best practice is to replace the TXV, flush lines where appropriate, and fit a new receiver‑drier or desiccant element. Many Subarus integrate the drier with the condenser—your technician will advise the correct approach for the exact variant.

Good clues that a TXV is the culprit rather than the compressor include solid cooling at highway speed but poor cooling at idle, frost on the evaporator outlet but not the inlet, or a low‑side line that’s too cold while the cabin still isn’t getting cool. A trained tech can confirm with gauges and temperature measurements in minutes.

• Is the TX valve on a 2009 Subaru Impreza a normal service item?
  Not usually. It’s replaced when faulty or if the system’s been contaminated. Regular “servicing” is really about keeping the rest of the system healthy—clean condenser, correct refrigerant charge, and a fresh cabin filter—so the TXV can control flow properly.
• Where is the TX valve located on a 2009 Impreza?
  It’s mounted at the evaporator on the passenger side. Access generally involves removing the glovebox/trim and disconnecting the A/C lines at the firewall. Exact steps vary slightly by body style and engine, so a licensed tech follows the Subaru service manual.
• Do you need to regas after replacing the TXV?
  Yes. Any time the system is opened, the refrigerant must be properly recovered, the system evacuated, and then recharged by weight to the specification shown on the under‑bonnet label. It’s a job for a licensed air‑con technician.