Parts for your 2013 Toyota Avensis-Temperature sensors

2013 Toyota Avensis temperature sensors — what they do and how to look after them

Per Toyota’s Avensis T27 workshop literature and wiring diagrams (Toyota Service Information/Techstream diagnostics, 2009–2018 T27), the 2013 Avensis absolutely uses multiple temperature sensors. These include the engine coolant temperature (ECT) sensor, intake air temperature (IAT) sensor (often integrated with the MAF), ambient air temperature sensor for the A/C and display, evaporator temperature sensor, automatic transmission fluid temperature sensor (on autos), and on diesel variants, exhaust gas temperature (EGT) sensors around the turbo/DPF. These are also documented across Denso component datasheets and common service manuals for the platform.

On this model, temperature sensors feed precise data to the engine and climate control ECUs, so the car can manage fuelling, ignition timing, idle speed, fan operation, transmission shift strategy, A/C operation, and (for diesels) DPF regeneration. Getting temperature right keeps cold starts smooth, economy tidy, emissions clean, and protects the engine from overheating out on Kiwi and Aussie roads.

• ECT: Governs warm-up enrichment, radiator fan control, temp gauge behaviour.
• IAT (often in the MAF): Adjusts fuelling and spark for air density changes.
• Ambient/evaporator: Keeps cabin temps comfy and prevents evaporator icing.
• ATF temp (auto): Tunes shift timing and line pressure when hot or cold.
• EGT (diesel): Protects turbo/DPF and times regen events.

Common signs a temp sensor’s gone off-colour include hard cold starts, high idle, poor fuel economy, cooling fans running flat out, erratic temperature gauge, A/C that won’t behave, or a MIL/CEL with codes like P0115–P0119 (ECT/IAT) or P0125.

They’re not routine “replace by kilometres” items, but they do appreciate attention during servicing. Recommended checks: scan for fault codes and live data with Techstream/OBD-II, inspect connectors for corrosion, verify coolant quality and level, and make sure grounds are clean. IAT/MAF units can be carefully cleaned with proper MAF cleaner—no touching the element.

Replacing an ECT sensor? Let the engine cool, relieve pressure, drain a litre or two of coolant below the sensor level, unplug the connector, swap the sensor (new sealing washer/O-ring as specified), torque to spec, then refill and bleed the cooling system. Use quality OEM-equivalent parts (Denso is common on Toyota). For diesels, EGT sensors can seize in the exhaust—use penetrating oil and take care with heat shields and brittle looms. Automatic transmission temp sensors are typically internal to the valve body, that’s a specialist job, often combined with fluid and filter service.

With a bit of care, the Avensis’ temperature sensors quietly keep everything humming along, from chilly South Island mornings to scorching Outback afternoons.

Popular questions

Where is the engine coolant temperature sensor on a 2013 Avensis?

On the 1.8 petrol (2ZR-FAE), it’s usually on the thermostat housing/water outlet at the gearbox side of the engine, under the intake. On the 2.0/2.2 D-4D (1AD/2AD), look near the coolant outlet by the EGR cooler area. Access often needs the engine cover off and a few hoses or the intake duct moved for space.

Will a bad temperature sensor trigger the check engine light?

Yes. The ECU will flag faults like P0115–P0119 (ECT/IAT) or P0125, and you might see fans running constantly, rich running, or hard starts. Reading live data will quickly confirm if a sensor’s reporting nonsense temps.

Is it safe to keep driving with a faulty temperature sensor?

Not ideal. A dodgy ECT/IAT can cause poor economy, rough running, and in the worst case, overheating. On diesels, incorrect temp data can upset DPF regens. If it’s drivable, keep trips short and get it checked pronto to avoid bigger bills.