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Parts for your 1998 Daihatsu Gran move-Temperature sensors
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1998 Daihatsu Gran Move temperature sensors — what they do and how to look after them
Based on the Daihatsu Gran Move (M100/M101 series) workshop literature for the HC‑EJ/K3‑VE engines and EFI wiring diagrams, plus Autodata service info covering the Gran Move/Charade platform, this model absolutely uses temperature sensors. The Engine Coolant Temperature (ECT) sensor feeds the ECU, there’s a separate sender for the dash gauge, and some variants also use the ECU’s temperature input to control radiator fan operation via a relay. These technical sources make temperature sensors directly relevant to how the 1998 Gran Move starts, fuels, and cools itself.
On this Gran Move, the ECT sensor is the quiet achiever. Cold or hot, it tells the ECU how warm the engine is so it can set fuelling, ignition timing, idle speed, and fan control. There’s typically a second sensor (sender) that runs the temperature gauge on the cluster, so the driver gets a clear read on engine temp. If either goes out of spec, owners might see hard starts, rough idle, richer fuel use, the radiator fan running at odd times, or a lazy temp gauge.
As part of routine servicing, a quick health check of the temperature sensors pays off. A scan tool reading for ECT that matches reality (cold start near ambient, warm idle around 85–95 °C) is a good sign. Stale coolant, corroded terminals, and trapped air can give sensors a hard time, so keeping the cooling system clean and properly bled helps them live longer.
- Inspect: Look for green/white corrosion at the sensor connector and brittle loom sheathing.
- Test: Compare scan-tool ECT to an infrared thermometer at the thermostat housing, if out by a mile, test sensor resistance per workshop specs.
- Replace: Work on a cold engine. Disconnect battery, relieve pressure, unplug the connector, remove the sensor, fit a new sealing washer/O‑ring as specified, torque correctly, refill coolant, and bleed air.
- Verify: Clear any fault codes, check for leaks, confirm fan operation, and recheck gauge behaviour on a road test.
Quality matters here. A decent OEM-equivalent ECT sensor and a fresh coolant mix will keep the Gran Move happy, help fuel economy, and save the head gasket from grief. If the dash gauge sender is flaky but the ECU reading is fine, replace the sender separately—on many cars they’re different parts with different threads and plugs.
Popular questions
Where is the coolant temperature sensor on a 1998 Gran Move?
The ECT sensor is typically threaded into the thermostat housing or cylinder head water outlet. It has a two‑pin plug and sits near the top hose area. The separate dash gauge sender is often nearby but usually has a single‑pin or different connector.
What are the symptoms of a failing temperature sensor?
Common signs include hard cold starts, high idle that won’t settle, poor fuel economy, the radiator fan running constantly or not at all, and a check‑engine light with temperature‑related fault codes. The dash gauge may read low or high if its sender is the culprit.
Do you need to bleed the cooling system after sensor replacement?
Yes. Any time the cooling circuit is opened, bleed air from the system. Refill with the correct coolant mix, run the engine with the heater on, squeeze the upper hose to purge bubbles, and top up the reservoir after the first heat‑cycle.
