Parts for your 2006 Nissan Pathfinder-Tx valve

2006 Nissan Pathfinder TX-valve: what it does, where it lives, and when to service it

Technical sources confirm the 2006 Nissan Pathfinder (R51) uses a thermostatic expansion valve (TX-valve). The Nissan Factory Service Manual (R51, 2006) in the HA/Heater & Air Conditioner section details an “Expansion Valve” at the evaporator, and models with rear A/C have a second “Rear Expansion Valve.” The Nissan FAST Electronic Parts Catalogue likewise lists front and rear expansion valve assemblies for R51, and major A/C parts catalogues (e.g., DENSO and Four Seasons) specify a TX-valve for 2005–2012 Pathfinder applications.

• Source: Nissan Factory Service Manual (R51, 2006), HA – Heating & Air Conditioning: Expansion Valve procedures and diagrams (front and, where equipped, rear).
• Source: Nissan FAST (Electronic Parts Catalogue) – R51 Pathfinder listings for front and rear expansion valves.
• Source: DENSO and Four Seasons application catalogues – Pathfinder R51 TX-valve fitment (front, plus rear on dual A/C models).

On the 2006 Pathfinder, the TX-valve meters refrigerant into the evaporator to keep superheat steady, which keeps the cabin cold without icing the core. It’s fitted at the front evaporator behind the dash on the passenger side, Pathfinders with rear air have a second valve at the rear evaporator in the right-hand rear quarter.

It isn’t a routine replacement item, but it’s central to stable, efficient cooling. Classic clues the TX-valve may be sticking or restricted include weak cooling at idle then overcooling on the highway, frosty suction lines, hissy or whooshing noises near the case, or front/rear temperature imbalance on dual-A/C models. Because the same symptoms can come from low refrigerant, a blocked cabin filter, a lazy condenser fan, blend door issues, or compressor wear, proper diagnosis with pressure/temperature readings against the FSM charts is the go.

When the valve is confirmed crook—or after compressor failure that spreads debris—replace it and fit new HNBR O-rings. Always renew the receiver–drier/desiccant, flush lines where allowed, and consider the condenser if it’s a parallel-flow type that can’t be properly flushed. Evacuate for at least 30 minutes, verify vacuum hold, then weigh in the exact R134a charge and the correct PAG oil quantity for the components replaced (per FSM). Use a torque wrench on the fittings and don’t overtighten. On rear-A/C models, inspect the long rear lines for corrosion near retainers and replace if pitted.

Good habits help: run the air-con regularly to keep seals oiled, keep the condenser fins clean, never “top up” without fixing leaks, and check for oil stains at the TX-valve joints during routine servicing. In Australia and New Zealand, refrigerant work must be carried out by a licensed A/C technician (ARCtick/AU or an approved filler/NZ).

Where is the TX-valve on a 2006 Pathfinder?
It’s mounted at the front evaporator inlet behind the dash on the passenger side. If the vehicle has rear A/C, there’s a second valve at the rear evaporator in the right rear quarter behind interior trim.

What symptoms point to a failing TX-valve?
Fluctuating vent temps, poor cooling at idle, line frosting near the firewall, and pressure readings that don’t match FSM charts. These overlap with low gas, condenser airflow issues, or compressor faults, so testing is key.

Should other parts be replaced with the TX-valve?
Yes—fit new O-rings and renew the receiver–drier. After compressor failure, flush where appropriate and consider replacing the condenser if contaminated. Complete evacuation and a weighed recharge are essential.