Parts for your 2006 Toyota Vitz|yaris-Temperature sensors

2006 Toyota Vitz/Yaris Temperature Sensors

Temperature sensors are absolutely fitted to the 2006 Toyota Vitz/Yaris (XP90 series) and they’re central to how the car runs and protects itself. Technical references that cover this include the Toyota Yaris (XP90) Repair Manual (Engine Control System), Toyota New Car Features for NCP90/91/93, the Electrical Wiring Diagram (EWD) for 2006 models, and the U340E/U341E automatic transaxle documentation. These sources detail multiple sensors: the engine coolant temperature (ECT) sensor, the intake air temperature (IAT) thermistor (typically built into the mass air flow meter), the air‑conditioning evaporator temperature sensor, the ambient temperature sensor (for A/C and display), and an automatic transmission fluid (ATF) temperature sensor on auto variants.

What do they all do? The ECT sensor tells the engine computer how hot the engine is so it can set cold‑start fuelling, ignition timing, idle speed, and fan operation. The IAT helps fine‑tune fuelling by gauging the air’s density. The evaporator sensor prevents the A/C from icing up. The ambient sensor helps the A/C and display keep things honest. On autos, the ATF temperature is used to adjust shift quality and protect the transmission.

While temperature sensors aren’t a routine “replace by kilometre” service item, they do deserve attention during regular servicing:

• Scan data check: With a scan tool, confirm ECT reads close to ambient when cold, then stabilises around 85–95°C at operating temp. IAT should be near ambient with the engine off.
• Visuals: Inspect plugs and looms for corrosion, broken tabs, coolant wicking, or oil contamination under the bonnet.
• Cooling system health: Use the correct Toyota SLLC coolant, don’t mix types, and keep the system bled—overheating can cook sensors and connectors.
• Replacement tips: If swapping the ECT sensor, safely drop coolant below the sensor level, fit a new O‑ring/seal, and torque to the spec in the Toyota manual. After refilling, bleed air and recheck readings.
• IAT/MAF: On most 2006 Yaris engines the IAT is inside the MAF. If IAT readings are wild, test the MAF thermistor