Parts for your 2015 Toyota Vitz|yaris-Temperature sensors

2015 Toyota Vitz/Yaris temperature sensors

Temperature sensors are absolutely fitted to the 2015 Toyota Vitz/Yaris and are central to how the car runs. Toyota’s repair literature for the XP130-series Vitz/Yaris (2011–2017) lists the Engine Coolant Temperature (ECT) sensor as a key input to the ECM with diagnostic codes P0115–P0119 and P0128. Toyota’s New Car Features (NCF) for 1NR-FE/1NZ-FE engines details the Intake Air Temperature (IAT) signal (often integrated in the MAF), and the Electrical Wiring Diagram (EWD) shows the Ambient Temperature Sensor feeding the A/C amplifier and combination meter. Automatic and CVT models also monitor Transmission Fluid Temperature (TFT) within the trans control system. So yes—temperature sensors are very much used on this model.

On a 2015 Vitz/Yaris, temperature sensors help the car start cleanly, use less fuel, and protect the engine and transmission. The ECT sensor tells the ECM how warm the engine is so it can adjust fuelling, ignition timing and when the cooling fans kick in. The IAT sensor helps the ECM tailor mixtures for hot Aussie/Kiwi summers or frosty mornings, keeping drivability tidy. The ambient temp sensor feeds the outside temperature display and helps A/C performance. Auto and CVT variants track transmission fluid temperature to manage shift strategy and torque-converter or CVT behaviour under load.

• Engine Coolant Temperature (ECT) sensor
• Intake Air Temperature (IAT) sensor (often in the MAF)
• Ambient temperature sensor (front grille area)
• Transmission fluid temperature sensor (auto/CVT)

There’s no routine replacement interval for these, they’re “fit and forget” until symptoms show. As part of regular servicing (every 10,000–15,000 km or 12 months, per local practice), it’s smart to:

• Scan for fault codes like P0115–P0119, P0128, P0071–P0073 if the MIL’s on or the fans misbehave.
• Visually check sensor connectors for corrosion, heat damage or broken clips under the bonnet and behind the grille.
• If the IAT is built into the MAF, clean the MAF gently with MAF-safe cleaner—never use carb/brake cleaner. Avoid over-oiling aftermarket filters.
• After front bumper repairs, confirm the ambient sensor is re-mounted and reading sensibly.

Replacing the ECT sensor is straightforward for a trained tech: work on a stone-cold engine, relieve system pressure, catch coolant, swap the sensor and seal, then refill with Toyota Super Long Life Coolant (pink) and bleed air with the heater on. If chasing odd temp readings, rule out a sticky thermostat or low coolant first. Transmission temp sensors on many CVTs are internal, diagnosis is via scan data and, if faulty, usually means transmission-internal work—best left to a specialist.

Popular questions

What are the signs the ECT sensor is failing on a 2015 Vitz/Yaris?
Hard cold starts, rich fuel use, high or hunting idle, cooling fans running when they shouldn’t, and a dodgy gauge reading are common. A scan tool may show P0115–P0119 or P0128. Always check coolant level and thermostat health as they can mimic sensor faults.

Can the intake air temperature sensor be cleaned instead of replaced?
If it’s integrated into the MAF (common on this model), a careful clean with MAF-specific cleaner can restore accurate readings. Don’t touch the sensing wire and avoid harsh solvents. If it’s a separate IAT, cleaning the connector and ensuring a snug fit often helps.

Do CVT models have a transmission fluid temperature sensor?
Yes. The CVT monitors fluid temp to protect the unit and manage ratios. It’s usually internal and not serviced on its own. If temps are off, check fluid level/condition and cooling first, then get a transmission specialist to assess with live data.