Parts for your 2006 Toyota Caldina-Temperature sensors

2006 Toyota Caldina temperature-sensors — purpose, care, and replacement

Temperature-sensors are absolutely fitted to the 2006 Toyota Caldina. Toyota’s technical literature for the T24-series Caldina (Repair Manual and Electrical Wiring Diagram), the Toyota parts catalogue, and standard OBD‑II diagnostics for its engines (1ZZ‑FE, 1AZ‑FSE and 3S‑GTE) all reference multiple temperature inputs: the Engine Coolant Temperature (ECT) sensor, Intake Air Temperature (IAT) sensor, ambient air temperature sensor (for the A/C and display), and an automatic transmission fluid (ATF) temperature sensor on auto models. OBD‑II trouble codes such as P0115–P0119 (ECT circuit range/performance) are specified for these engines, confirming the vehicle relies on these sensors.

On this Caldina, the ECT sensor tells the ECU how hot the engine is so it can sort cold starts, fuelling, ignition timing, VVT‑i behaviour, radiator fan operation, and the cluster gauge. The IAT sensor (often integrated in the MAF on 1ZZ/1AZ engines) fine‑tunes fuel delivery by measuring incoming air temp. Auto models read ATF temperature to manage shift quality and protect the gearbox, while the ambient sensor supports the climate control and outside‑temp display.

These sensors aren’t a scheduled replacement item, but they wear with age and heat. Rough cold starts, high idle when warm, lazy fans, a wandering temp gauge, poor fuel economy, or a Check Engine light can point to a dodgy sensor or connector. As part of routine servicing, a quick sensor health check is well worth it.

• Scan live data from a cold start: ECT should read close to ambient, then climb smoothly to operating temp (roughly low‑90s °C).
• Visually inspect the ECT connector and wiring under the bonnet for corrosion, cracked plugs, or coolant crust.
• If testing off‑car, compare resistance to temperature using the service manual chart.
• Keep the cooling system healthy: renew Toyota Super Long Life Coolant (pink) per schedule, and fix leaks early.

If replacement’s needed, let the engine cool fully, relieve pressure, and catch the coolant. Swap the sensor on the thermostat housing/water outlet (location varies slightly by engine). Use a new sealing washer/O‑ring as specified