Parts for your 2002 Daihatsu Gran move-Tx valve

2002 Daihatsu Gran Move TX Valve — what it does and how to look after it

Referencing technical sources, including the Daihatsu Gran Move/Pyzar workshop manual HVAC section and Denso/aftermarket parts catalogues, the 2002 Gran Move uses a thermostatic expansion valve (TXV) mounted at the evaporator inlet. So this model is TXV‑equipped rather than an orifice‑tube/accumulator setup.

The TXV’s job is to meter R134a into the evaporator based on the sensing bulb’s temperature feedback and system pressure, holding the right superheat. That keeps the evaporator nice and cold without letting liquid refrigerant make it back to the compressor. Because it constantly trims flow, it smooths out cabin temps at idle and on the open road, adapting to load changes like ambient heat, blower speed and engine rpm. In short, it’s the brains of the cooling side of the Gran Move’s air‑con.

TXVs aren’t a scheduled replacement item, but they can stick or clog. Classic telltales include weak cooling, big swings in vent temperature, frosting or heavy condensation at the firewall pipes, a persistent hiss at the case, and pressure readings that show a starved or flooded evaporator. A stuck‑closed valve usually gives low suction and warm vents, stuck‑open can cause poor cooling control and potential compressor distress. After a compressor failure or any time the system’s been open to atmosphere, the valve is more likely to be contaminated and is often replaced as good practice.

When servicing the Gran Move’s TXV, a licensed air‑con tech should:

• Recover the refrigerant legally (ARCtick in AU, licensed handling in NZ) and open the system safely.
• Replace the receiver‑drier, and flush lines if there’s debris or “black death”.
• Renew HNBR O‑rings, lubricated with the correct PAG oil for the compressor family.
• Install and insulate the valve and sensing bulb exactly as per the manual, torque fittings correctly.
• Evacuate, leak test, then recharge R134a to the specified weight, avoid topping by “feel”.
• Verify superheat and pressures, and check airflow items (condenser cleanliness, fan operation).

Good habits help the valve live longer: run the A/C for 10–15 minutes each week, keep the condenser fins clean, and change the cabin filter if fitted. Always use quality parts (OE‑spec/Denso) and don’t mix oils or refrigerants. Tiny part, big job — on a 2002 Gran Move, a healthy TXV is the difference between “meh” and mint, ice‑cold air on a scorching arvo.

Popular questions about the 2002 Daihatsu Gran Move TX valve

Does the 2002 Gran Move use a TX valve or an orifice tube?
This model uses a thermostatic expansion valve at the evaporator inlet with a receiver‑drier in the high side, which is typical for Japanese vehicles of the era. It isn’t an orifice‑tube/accumulator system.

When should the TX valve be replaced on a Gran Move?
There’s no time‑based interval. Replace it when diagnostics confirm a faulty or contaminated valve, particularly after compressor failure or whenever the system has been open and moisture or debris may have entered.

Can a DIYer change the TX valve at home?
Because refrigerant handling is regulated in Australia and New Zealand, recovery and re‑gassing must be done by a licensed technician. The job also needs correct torque, insulation placement and charge by weight, so professional service is the smart move.