Parts for your 2013 Subaru Legacy-Temperature sensors

2013 Subaru Legacy temperature-sensors — what they do and when to service them

Based on Subaru technical documentation, temperature-sensors are absolutely used on the 2013 Subaru Legacy. The Subaru Factory Service Manual for the 2013 Legacy/Outback details the Engine Coolant Temperature (ECT) sensor and Intake Air Temperature (IAT) input in the Engine (Diagnostics) section, the TR580 CVT chapter covers the transmission fluid temperature sensor, and the HVAC section lists the ambient/outside air and evaporator temperature sensors. Relevant OBD-II diagnostics (e.g., P0115–P0119 for ECT, P0111–P0113 for IAT, and P0711 for ATF temperature) further confirm their presence. These sources collectively establish that multiple temperature-sensors are integral to this model.

On a 2013 Subaru Legacy, temperature-sensors quietly keep the whole show running right. The engine coolant temperature sensor lets the ECU know how warm the engine is so it can sort cold-start fuelling, ignition timing, idle speed, radiator fan operation and the dash gauge. The intake air temperature reading fine-tunes fuelling as the weather swings from a frosty morning to a scorcher. The CVT’s internal fluid temperature sensor protects the transmission by managing line pressure and shift strategy, while the outside and evaporator sensors help the climate control deliver steady cabin comfort.

There’s no fixed replacement interval for these solid-state sensors, but they deserve a look-in at every service (roughly every 10–15,000 kilometres). A few smart checks go a long way:

• Scan live data to see coolant, intake and CVT temps behaving plausibly from cold start to operating temperature.
• Inspect connectors for green crust, broken locks or chafed wiring—especially around the thermostat housing, radiator support and MAF/IAT area.
• Keep coolant fresh and the system bled properly, air pockets can mimic a bad ECT.
• For IAT (often integrated in the MAF on this model), clean only with proper MAF cleaner—never brake or carb spray.
• Make sure the outside temp sensor in the grille isn’t blocked by leaves or road grime.

Warning signs that a temperature-sensor is on the fritz include hard cold starts, rough idle when warm, fans running at odd times, poor fuel economy, a dead A/C compressor due to evaporator icing logic, or a Check Engine Light with codes like P0115, P0117, P0118, P0111 or P0711. If replacement is needed, go with quality OEM-equivalent parts. For the ECT, only remove it on a stone-cold engine, catch and refill coolant, and tighten to the specified torque—aluminium threads don’t love over-enthusiastic spanners. The CVT fluid temp sensor is internal, diagnosis is via scan data and, if it’s running hot, a fluid service and cooling system check are the first ports of call. Done right, these little sensors keep the Legacy feeling crisp, efficient and happy under the bonnet.

Technical basis referenced: Subaru 2013 Legacy/Outback Factory Service Manual—Engine (Diagnostics) ECT/IAT inputs, Air Intake (MAF/IAT) section, Automatic Transmission/Transaxle (TR580 CVT) ATF Temperature Sensor, HVAC ambient and evaporator temperature sensors, OBD-II DTCs P0115–P0119, P0111–P0113, P0711.

Popular questions

Where is the engine coolant temperature sensor on a 2013 Legacy?
On FB25 four-cylinder models it’s mounted near the thermostat housing/coolant outlet at the front of the engine, close to the upper radiator hose. It’s accessible from the top—unclip the connector, then unscrew the sensor. On six-cylinder variants it’s positioned on the front coolant crossover. Always let the engine cool before touching it.

Is the intake air temperature sensor separate from the MAF?
On most 2013 Legacy trims, the IAT element is integrated into the mass airflow sensor on the air intake tube. Some markets may have a separate IAT in the airbox. If cleaning, use only dedicated MAF cleaner and allow it to dry fully before refitting.

Do temperature-sensors need routine replacement?
No scheduled interval is specified. They’re checked by symptoms and scan-tool data. Replace a sensor if it’s out of spec, shows erratic readings, or triggers relevant DTCs. Preventative care focuses on clean connectors, sound wiring, correct coolant, and proper bleeding after cooling-system work.