Parts for your 2000 Toyota Bb-Tx valve

2000 Toyota bB TX valve: purpose, servicing and replacement

Yes, the 2000 Toyota bB is fitted with a TX valve (thermal expansion valve) in its factory Denso air-conditioning system. Technical references include the Toyota bB (NCP30/NCP31) Repair Manual sections for “Air Conditioning – Cooling Unit – Cooler Expansion Valve,” the Toyota Electronic Parts Catalogue listing “Valve Sub‑Assy, Cooler Expansion” for NCP30 models, and Denso service literature that outlines Toyota’s use of TXV-and-receiver layouts on late‑90s/early‑2000s passenger vehicles. So, a TX valve is relevant to this model’s A/C servicing and performance.

The TX valve’s job is to meter the flow of R‑134a into the evaporator, responding to evaporator outlet temperature and pressure. By controlling superheat, it keeps the evaporator cold without letting it ice up, which means steadier vent temps, better demist performance, and less strain on the compressor. When a TX valve sticks, clogs, or mis-meters, drivers often notice weak cooling at idle, vents going warm then cold, hissing at the firewall, or a frosty evaporator case with poor cabin cooling.

On the 2000 bB, the TX valve is mounted at the evaporator inlet inside the HVAC box, accessed from the passenger side behind the glovebox where the A/C pipes pass through the firewall. Because it sits at the heart of the cooling unit, proper replacement and commissioning are key. A competent technician will: recover the refrigerant, remove the glovebox/trim, disconnect the A/C lines, replace the TX valve and all O‑rings, and generally renew the receiver/drier any time the system is opened. After reassembly, they’ll evacuate the system with a vacuum pump, leak-test, and recharge with the exact R‑134a weight shown on the under‑bonnet label, adding the specified PAG oil amount for any parts replaced.

As part of routine servicing in Aussie and Kiwi conditions, it’s smart to inspect for oily residue at the firewall connections, check for fluctuating high/low pressures during A/C performance tests, and listen for chatter or constant hissing. Keeping the cabin filter clean and the condenser fins free of debris helps the TX valve do its job. If contamination is suspected (compressor failure, moisture ingress), the valve can gum up—so always pair any major A/C repair with a receiver/drier replacement and a thorough flush where appropriate. Done right, the bB’s TX valve will provide crisp, reliable cooling through long, hot summers.

• Common symptoms of TX valve trouble: intermittent cooling, evaporator icing, noisy hissing, abnormal pressure readings.
• Best practice on replacement: new O‑rings, renew receiver/drier, correct oil balance, vacuum, and precise recharge by weight.

Popular questions

Does the 2000 Toyota bB use a TX valve or an orifice tube?
It uses a TX valve. Toyota’s bB (NCP30/NCP31) cooling unit is a Denso TXV system with a receiver/drier, not a fixed orifice tube. This setup provides tighter control of evaporator superheat and steadier vent temperatures.

Where is the TX valve located on a 2000 Toyota bB?
It’s mounted at the evaporator inlet inside the HVAC box behind the glovebox, where the A/C pipes pass through the firewall. Access is from the passenger side, trim removal is usually required to reach the fittings and the valve.

When should the TX valve be replaced on a bB?
Replace it if there’s confirmed metering fault, internal blockage, or contamination after a compressor event. Any time the system is opened for major A/C work, renewing the TX valve and receiver/drier is wise. Always evacuate and recharge to the exact R‑134a weight shown under the bonnet.