Parts for your 2007 Toyota Vitz|yaris-Temperature sensors

2007 Toyota Vitz/Yaris temperature sensors — what they do and how to look after them

Temperature sensors absolutely are fitted and relevant on the 2007 Toyota Vitz/Yaris (XP90 series). Technical documentation confirms multiple temp sensors are used: the Engine Coolant Temperature (ECT) sensor for the ECU and gauge data, an Intake Air Temperature (IAT) sensor integrated with the MAF, an Automatic Transmission Fluid (ATF) temperature sensor on auto models, and A/C-related temperature sensors depending on spec. Sources: Toyota Yaris/Vitz 2006–2011 Repair Manual (Engine Control System sections for ECT and IAT), Toyota Electrical Wiring Diagram (EWD) for NCP9# models, Denso application catalogue for 1NZ-FE/2NZ-FE sensors, and SAE J1979/ISO 15031 OBD-II documentation that specifies ECT/IAT PIDs and related DTCs (e.g., P0115–P0119).

On this Vitz/Yaris, the temperature sensors play a quiet but critical role. The ECT sensor tells the ECU how warm the engine is so it can sort the fuel mix, ignition timing, idle speed, and when to kick in the radiator fans. The IAT helps with fuelling by reporting incoming air temperature. Auto models also watch ATF temp to manage shift behaviour and protect the transmission. If the info’s wrong, cold starts get grumpy, fuel economy suffers, the gauge can act odd, and fans may run at the wrong time.

There’s no fixed replacement interval for the ECT or IAT—change them when they’re faulty. As part of routine servicing, it’s smart to:

• Scan live data for coolant and intake temps to make sure readings look realistic from cold start to operating temp.
• Inspect connectors under the bonnet for corrosion, oil wicking, or brittle plastic.
• Keep the cooling system healthy—use Toyota Super Long Life Coolant (pink) and follow service intervals (first change at around 160,000 km or 10 years, then about every 80,000 km or 5 years).

When replacing an ECT sensor on the 1.3 or 1.5-litre engines, work on a cool engine, expect a little coolant loss, and fit a new gasket/O-ring as supplied. Tighten to the workshop spec (around 20 N·m on many 1NZ/2NZ engines—always confirm in the repair manual). After refilling, bleed air from the cooling system, run the heater hot, and check for leaks. Use genuine or quality OEM-equivalent parts for consistent readings.

Signs it’s time to test a temp sensor include hard cold starts, black smoke or rich running, the radiator fans cycling oddly, an erratic temp gauge, or a Check Engine lamp with codes like P0115–P0119. A quick scan and a multimeter check can usually pinpoint the culprit without guesswork.

FAQs

Where is the engine coolant temperature sensor on a 2007 Vitz/Yaris?
It’s threaded into the coolant outlet/thermostat housing area on the engine. On the 1NZ-FE/2NZ-FE, look near the transmission side of the head where the upper radiator hose meets the engine. Access is straightforward with basic hand tools. Always let the engine cool before removal to avoid scalding coolant.

If unsure, confirm location and torque in the Toyota repair manual for your exact engine code, and verify operation with live data on a scan tool.

What are common symptoms of a faulty ECT sensor?
Typical giveaways include rough or rich cold starts, poor fuel economy, a temp gauge that doesn’t make sense, radiator fans running constantly or not at the right time, and OBD-II codes such as P0115–P0119. The sensor itself won’t cause true overheating, but it can misreport temperature, which confuses the ECU and the gauge.

Before replacing, check the connector for corrosion and compare the sensor’s live readings to actual engine temperature from cold to hot.

Does this Yaris have more than one temperature sensor?
Yes. Beyond the ECT, there’s an IAT sensor (usually in the MAF), an ATF temperature sensor on automatic transmissions, and A/C-related temperature sensors depending on trim. The instrument cluster typically displays coolant temperature using data broadcast from the ECU rather than a separate sender.

That’s why scanning live data is so handy—you can see multiple temperature channels at once and pinpoint which circuit needs attention.