Parts for your 2008 Subaru Legacy-Temperature sensors

2008 Subaru Legacy temperature sensors

Temperature sensors absolutely are fitted and relevant on the 2008 Subaru Legacy. The Subaru Factory Service Manual for the 2008 model (Engine Diagnostics and HVAC sections) details the Engine Coolant Temperature (ECT) sensor and related control logic. Subaru Technical Information System wiring diagrams show an Intake Air Temperature (IAT) sensor (often integrated with the MAF on EJ engines), an ambient air temperature sensor for the climate control/outside temp display, and an Automatic Transmission Fluid (ATF) temperature sensor on auto models. Standard OBD‑II diagnostics for this car also include temperature-sensor DTCs such as P0115–P0119 (ECT), P0110 (IAT), and P0711 (ATF temp), confirming these sensors are used across the range.

On a 2008 Legacy, temperature sensors help the engine and gearbox behave properly across Aussie and Kiwi conditions—from frosty mornings to scorching arvos. The ECT sensor tells the engine computer how hot the coolant is so it can set fuel, ignition timing, idle speed, and when to switch the radiator fans. The IAT sensor helps with fuel trim by tracking incoming air density. The ambient sensor feeds the climate control and outside temperature display. Autos rely on an ATF temp sensor so the transmission control module can protect the gearbox when fluid gets too hot.

• Engine Coolant Temperature (ECT): Fuelling, timing, idle, radiator fan control, overheat warnings.
• Intake Air Temperature (IAT): Air‑fuel calculations, cold‑start enrichment, knock avoidance.
• Ambient temperature (HVAC/cluster): Climate control performance and outside temp read‑out.
• ATF temperature (auto only): Shift strategy and thermal protection.

If a sensor goes south, drivers may see hard cold starts, high idle, rich running, the thermo fans stuck on, lazy A/C, or a Check Engine Light with codes like P0115 or P0110. Servicing is straightforward: sensors aren’t routine “consumables”, but they should be inspected whenever the cooling system, intake, or transmission is serviced. Check connectors for corrosion, brittle housings, and damaged loom sections. When replacing an ECT sensor, use a quality OEM‑spec part, fit a new sealing washer or O‑ring, avoid sealant unless the manual specifies it, torque to spec, and bleed the cooling system properly. For IAT integrated with the MAF, clean only with MAF‑safe cleaner and replace the unit if readings drift. The ATF temp sensor is typically internal