Parts for your 2003 Toyota Highlander-Tx valve

2003 Toyota Highlander TX-Valve (Expansion Valve)

Technical references including the Toyota Repair Manual (A/C section on “Cooler Expansion Valve” for XU20/MCU2#), Toyota’s Electronic Parts Catalogue listing an “A/C Expansion Valve,” and DENSO OE catalogues all confirm that the 2003 Toyota Highlander (also known as Kluger in AU/NZ) is fitted with a thermostatic expansion valve (TXV) at the evaporator. So yes—the TX-valve is relevant and used on this model.

On this Highlander, the TX-valve’s job is to meter the right amount of R-134a into the evaporator, reacting to temperature and pressure to maintain proper superheat. That clever metering is what keeps cabin temps stable, helps prevent icing, and gets the most out of the air-con without overworking the compressor.

As part of regular servicing, the TX-valve isn’t a routine replacement item. However, when performance drops—think warm air at idle, vent temps that swing hot–cold, evaporator frosting, or odd hissing—techs will test system pressures and often zero in on a sticking or restricted TXV. If the compressor has failed (black death), debris can jam the valve, in those cases, a new TX-valve, receiver/drier (or desiccant bag), thorough line flushing, and the correct PAG oil quantity are the go-to steps.

Owners and workshops should keep a few points in mind:

• Access is typically at the evaporator inlet on the HVAC case behind the glovebox, so interior trim removal is part of the job.
• Always replace the O-rings, lightly lubricated with the specified refrigerant oil, and torque fittings to the values in the Toyota manual.
• After fitting, evacuate the system properly, leak-test, and charge to the factory-specified weight shown on the under-bonnet label.
• If moisture or contamination is suspected, replace the receiver/drier and consider flushing to protect the new valve.

Using quality OE or OE-equivalent parts (DENSO supplies Toyota from factory) keeps the Highlander’s air-con crisp on scorching Aussie and Kiwi summer days. Because handling refrigerant is regulated, it’s best left to a licensed air-con tech with the right recovery gear and gauges.

Popular questions about the 2003 Toyota Highlander TX-valve

Where is the TX-valve located on a 2003 Highlander?
It’s mounted at the evaporator inlet on the HVAC case, typically behind the glovebox. Access usually involves removing the glovebox and related trim to reach the valve and line fittings.

What are the signs the TX-valve needs replacing?
Common clues include poor cooling at idle, vent temperatures that fluctuate, evaporator icing, and pressure readings that show abnormally high high-side with starved low-side—or the reverse if the valve is stuck open.

Does this model use a TX-valve or an orifice tube?
This generation Highlander/Kluger uses a thermostatic expansion valve, not a fixed orifice tube. Toyota’s service procedures and parts listings specify a TXV at the evaporator.