Parts for your 2019 Toyota Vitz|yaris-Temperature sensors

2019 Toyota Vitz/Yaris temperaturesensors — what they do, and how to look after them

Based on Toyota technical literature and diagnostic data, temperaturesensors are absolutely fitted and relevant on the 2019 Toyota Vitz/Yaris (NCP/NSP/KSP/NHP130 series). The Toyota Repair Manual and Electrical Wiring Diagram list the Engine Coolant Temperature (ECT) sensor, Intake Air Temperature (IAT) sensor (often built into the MAF), ambient air temperature sensor for the A/C/display, and a CVT fluid temperature sensor within the transmission. These are monitored by the ECM/TCM and A/C amplifier, with standard OBD-II fault codes (e.g., P0115–P0119 for ECT, P0111–P0113 for IAT, P0711/P0713 for CVT). Without these, closed-loop fuelling, ignition timing, idle speed, fan control, and climate performance wouldn’t meet emissions and driveability targets.

On this Vitz/Yaris, temperaturesensors tell the car how hot or cold things are so it can run sweet as. The ECT sensor helps the ECM set fuel and timing when cold, kicks on the radiator fans, and protects the engine under the bonnet on scorching days. The IAT sensor trims fuelling based on incoming air density. The ambient sensor feeds the dash and A/C so it doesn’t blow too hot or too cold. CVT models use fluid temperature to manage shift strategy and protect the transmission. Hybrids add battery/coolant temp monitoring as well.

There’s no fixed replacement interval for these sensors, they’re replaced on condition. As part of routine servicing, a workshop should scan live data from cold start to operating temp to confirm the ECT and IAT read plausibly (cold values near ambient, smooth warm-up to the low 90s °C). They’ll also inspect connectors and looms for corrosion or rub-through, and confirm cooling fans cycle as expected. Keeping Toyota Super Long Life Coolant fresh (first change typically at 160,000 km/10 years, then 80,000 km/5 years) protects the ECT and helps accurate readings. A clean air filter and, if appropriate, a gentle MAF/IAT clean with proper sensor-safe spray can prevent skewed IAT readings. CVT fluid service to spec helps the internal temp sensor report accurately, the sensor itself is generally part of the valve body harness rather than a separate service item.

• Common clues a temperaturesensor is crook: hard cold starts, rough idle, poor fuel economy, fans running constantly or not at all, sluggish A/C, or the MIL on.
• Typical fault codes: ECT (P0115–P0119, P0125/P0128), IAT (P0111–P0113), CVT temp (P0711/P0713), ambient temp (A/C codes via the A/C amplifier).

Replacement of the ECT on most 1.3L/1.5L engines is straightforward for a pro: allow the engine to cool, drain a little coolant, swap the sensor at the thermostat housing or cylinder head, reconnect the two-pin plug, top up and bleed coolant, then verify readings with a scan tool. Using genuine-grade parts and correct coolant is the safest way to keep the 2019 Toyota Vitz/Yaris happy across Aussie and Kiwi conditions.

Where is the engine coolant temperature sensor on a 2019 Toyota Vitz/Yaris?

On most 1.3L/1.5L petrol variants it’s fitted near the thermostat housing or on the cylinder head, close to the upper radiator hose outlet, with a two-pin connector. Access is under the bonnet from the top, allow the engine to cool before touching anything hot or pressurised.

What fault codes point to a bad temperaturesensor on this model?

For the ECT: P0115–P0119 and sometimes P0125/P0128 if the engine isn’t reaching temp. For IAT (often in the MAF): P0111–P0113. For CVT fluid temp: P0711/P0713. Ambient temp sensor faults can show in the A/C system scan data. Always confirm with live data rather than codes alone.

Do temperaturesensors need periodic replacement on a 2019 Vitz/Yaris?

No set interval. They’re replaced if readings are implausible, if there are relevant DTCs, or if physical damage/corrosion is found. Preventative care includes fresh coolant at the correct interval, a clean air filter, sensor-safe MAF/IAT cleaning if appropriate, tidy wiring, and proper CVT fluid service on CVT models.