Parts for your 1997 Daihatsu Gran move-Temperature sensors

1997 Daihatsu Gran Move Temperature Sensors — What They Do and How to Look After Them

Temperature sensors are absolutely fitted to the 1997 Daihatsu Gran Move (also known as the Pyzar in some markets). Technical sources including the Daihatsu Gran Move/Pyzar G3-series workshop manual (EFI section), the Daihatsu Electronic Parts Catalogue (G303/G313 listings), and standard Denso EFI documentation confirm the presence of an Engine Coolant Temperature (ECT) sensor and an Intake Air Temperature (IAT) sensor on the fuel-injected HC-series engine. Many variants also use the ECT input for radiator fan control via the ECU, and some markets may include a separate thermo-switch or a separate single-wire sender for the dash gauge.

On this Gran Move, the ECT sensor tells the ECU how hot the engine is so it can sort cold-start enrichment, idle speed, ignition timing and when to kick the cooling fan on. The IAT sensor helps fine-tune fuelling and timing based on incoming air temperature. If either goes out of range, it can cause rough running, poor economy and annoying hot or cold start issues.

They’re not “consumables” with a set replacement interval, but they do age. As part of routine servicing, it’s smart to check that the connectors are clean and snug (the ECT sits near the thermostat housing, so it cops heat and moisture), confirm there’s no green crust on terminals, and make sure coolant is clean and at the right mix—contaminated coolant can accelerate sensor decay and alloy corrosion.

• Typical symptoms of a dodgy ECT/IAT: hard starting when cold, rich smell, high fuel use, hunting idle, cooling fan stuck on or never coming on, and an engine light with a temp-sensor fault code stored.
• Basic checks: scan for fault codes, compare live temperature readings to reality, or measure sensor resistance against workshop-manual specs at known temperatures.
• Replacement tips: use the correct spec sensor, fit a new sealing washer or O-ring, lightly coat threads if specified (avoid excess sealant), torque to the manual spec, top up and bleed the cooling system, then recheck for leaks and confirm fan operation.

Plenty of owners opt to replace a tired ECT around the 150–250,000 km mark or when doing a thermostat and coolant change, simply because it’s easy access and cheap insurance. Keeping the connectors tidy and the coolant fresh goes a long way toward happy motoring.

Technical sources referenced: Daihatsu Gran Move/Pyzar G3-series Workshop Manual (Engine Control/EFI sections), Daihatsu Electronic Parts Catalogue (G303/G313) listings for ECT and IAT, Denso electronic fuel injection fundamentals for temperature sensing.

FAQs

Where is the coolant temperature sensor on a 1997 Gran Move?
It’s typically threaded into or near the thermostat housing at the cylinder head end. Expect a two-wire plug for the ECU. Some cars also have a separate single-wire sender for the dash gauge, so you may see two devices in the same area.

Can a faulty temperature sensor be cleaned, or should it be replaced?
The sensor tip itself isn’t a service item—if it’s out of spec, replace it. You can clean the electrical connector and pins with contact cleaner and apply dielectric grease. If issues persist after connector TLC, fit a new sensor.

Do I need to drain the coolant to replace the ECT sensor?
Partially, yes. You can minimise loss by dropping the level below the thermostat housing, but have a tray and rags ready. After replacement, refill with the correct coolant mix and bleed air from the system so the fan cycles properly and the heater blows hot.