Parts for your 1992 Toyota Caldina-Temperature sensors

1992 Toyota Caldina temperature sensors — what they do and how to look after them

Temperature sensors are absolutely fitted to the 1992 Toyota Caldina. Toyota’s Electronic Parts Catalogue for the ST190/CT190 series (1992–1995) lists the engine coolant temperature (ECT) sensor (commonly catalogued under item 89422) and a separate sender for the instrument cluster. Toyota’s EFI/Engine Control System manuals for engines used in the Caldina (such as 4A-FE and 3S-FE) also describe the ECT signal as a primary ECU input for fuel and ignition control, with some variants using either an ECU-controlled fan or a dedicated thermo fan switch.

On a ’92 Caldina, temperature sensors quietly keep everything in the sweet spot. The ECT sensor feeds the ECU a live read on coolant temperature so it can adjust fueling, ignition timing and cold-start enrichment. There’s also a sender that runs the dash gauge, and—depending on engine and market—a thermo fan switch or ECU strategy for the radiator fan. If any of these go off song, the car can run rich, idle high, use more fuel than it should, or the fans might misbehave under the bonnet.

As part of routine servicing, it’s smart to give the temperature-sensor system a once-over whenever the cooling system is being worked on (coolant change, thermostat, hoses). Check the connectors for green crust or broken locking tabs, ensure the wiring isn’t brittle, and confirm the fans cycle normally at operating temperature. If the check engine light is on with an OBD1 Code 22 (typical Toyota ECT fault), test the sensor’s resistance against temperature