Parts for your 2005 Honda Elysion-Tx valve

2005 Honda Elysion TX-Valve: What it does and when to service it

Based on Honda technical information and parts catalogues for the Elysion (RR1–RR4, 2004–2008) and its closely related Odyssey platform, the 2005 Honda Elysion uses a thermostatic expansion valve (TX-valve) at the front evaporator, and models equipped with rear air conditioning have a second TX-valve at the rear evaporator. This is supported by Honda HVAC service literature describing block-style expansion valves at the evaporator inlet, and by OEM parts listings that catalogue “EXPANSION VALVE” components for the Elysion’s air conditioner assemblies.

On this Elysion, the TX-valve meters liquid R‑134a into the evaporator, reacting to outlet temperature (and often pressure) so the evaporator runs at the sweet spot: cold enough to pull heat and moisture from the cabin without icing up. When it’s healthy, you get steady vent temps, quick pull-down on hot days, and no odd cycling or frosting. Many Elysions in Australia and New Zealand also have rear A/C, so there’ll be a front and a rear TX-valve doing the same job for each evaporator.

Signs the valve’s on the fritz include weak cooling at idle but not on the highway, vent temperatures that swing hot–cold, hissing at the dash, frosting at the valve or evaporator inlet, and pressure readings that are too high or too low for conditions. Because those symptoms can also come from a blocked cabin filter, low refrigerant charge, a tired compressor, or a restricted receiver–drier, diagnosis should be done with proper gauges and temperature checks.

Replacement or service isn’t a routine, time-based item, it’s condition-based. If a TX-valve sticks, clogs with debris or moisture, or its sensing bulb loses charge, it’s time to replace it. On the 2005 Elysion, the front valve is typically mounted at the evaporator in the HVAC case, rear valves live near the rear evaporator. Any work on refrigerant must be handled by a licensed A/C technician—recovery, vacuum, and precise recharging are mandatory. Smart practice is to renew O-rings, inspect/replace the receiver–drier or desiccant element when the system’s opened, and flush lines if there’s contamination. After refit, a deep vacuum, leak test, and charging to spec with R‑134a keeps the system happy.

To help the TX-valve do its job, keep the cabin filter fresh, ensure condenser fins are clean and straight, and fix any condenser fan faults promptly. Those small steps reduce system head pressure, improve cooling, and extend the life of both TX-valve and compressor.

• Technical sources consulted: Honda Elysion (RR1–RR4) Electronic Parts Catalogue – Air Conditioner section (lists expansion valve parts), Honda Odyssey RB1/RB2 2005 HVAC service procedures (block-type TXV at evaporator), OEM supplier literature (Denso/Keihin) on automotive TXV operation in dual-evaporator systems.

Popular questions about the 2005 Honda Elysion TX-valve

Does the 2005 Elysion have one or two TX-valves?
Most Australian and New Zealand–delivered Elysions with rear A/C have two: one for the front evaporator and one for the rear. If the vehicle is front A/C only, it’ll have a single TX-valve at the front unit.

When should the TX-valve be replaced?
There’s no set interval. Replace it when symptoms and pressure/temperature diagnostics point to a sticking or restricted valve, or whenever the system has suffered contamination or moisture ingress. If the system is opened, consider renewing the desiccant and relevant O‑rings.

Can a dirty cabin filter affect the TX-valve?
Indirectly, yes. A clogged filter reduces airflow across the evaporator, which can drive odd temperature behaviour that looks like a TX-valve fault. Always check the cabin filter and condenser airflow before condemning the valve.