Parts for your 2013 Toyota Avensis-Temperature sensors

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

Temperature sensors are absolutely fitted to the 2013 Toyota Avensis (T27). Toyota’s Repair Manual and Electrical Wiring Diagram for the Avensis, plus Autodata and Haynes coverage for 2009–2018 models, detail multiple sensors: the engine coolant temperature (ECT) sensor, intake air temperature (IAT) sensor (often built into the MAF on petrol engines), ambient air temperature sensor for the climate control, transmission fluid temperature sensor on automatics, and (on D-4D diesels) exhaust gas temperature (EGT) sensors used with the DPF. These systems are also consistent with principles in the Bosch Automotive Handbook.

On this Avensis, temperature sensors let the ECU fine‑tune fuelling, ignition, idle speed, radiator fan operation, and auto shift strategy, while the HVAC system uses ambient temperature to keep the cabin comfy. Diesel models rely on EGT sensors to manage DPF regeneration and protect the turbo. When a sensor drifts or fails, owners might notice hard cold starts, rough running, poor fuel economy, fans running when they shouldn’t, erratic outside temperature readings, or a DPF warning. Fault codes like P0115–P0119 (ECT) or P0071–P0073 (ambient/IAT) are common flags.

During routine servicing, temperature sensors aren’t “replace on schedule” items, but they should be checked. A quick scan with Techstream or a quality OBD tool on a stone‑cold engine should show ECT and IAT close to the day’s ambient. If the numbers look off, dig deeper before parts swapping.

• Inspect plugs and wiring near the thermostat housing, radiator fans, MAF/IAT and front bumper (ambient sensor). Look for corrosion, broken clips or chafed looms.
• Clean a dirty MAF/IAT using dedicated MAF cleaner only. Avoid spraying the IAT bead directly and never use throttle body cleaner on it.
• Keep coolant fresh (Toyota SLLC pink). Old coolant can attack sensors and skew readings. Bleed air properly after any cooling‑system work.
• Replacing an ECT sensor? Let it cool, catch the coolant, use the correct seal (O‑ring or washer), don’t over‑tighten, and verify readings on a scan tool.
• Diesel EGT sensors can seize in the exhaust. Use penetrating oil, heat if needed, and a proper sensor socket. After replacement, check for DPF readiness and clear learned values if specified in the service info.
• Automatic transmission temp sensors live inside the unit