Parts for your 2015 Subaru Outback-Temperature sensors

2015 Subaru Outback temperature sensors: what they do and how to look after them

Based on Subaru’s 2015MY Outback Factory Service Manual (BS chassis) and wiring diagrams in Subaru’s service information, plus OEM parts catalogues, this model absolutely uses multiple temperature sensors. They’re integral to engine, transmission and climate control operation, so they’re relevant to any servicing plan for a 2015 Subaru Outback.

These sensors constantly feed the car’s control modules with temperature data so the vehicle can run smoothly, efficiently and safely. They affect cold starts, fuel economy, emissions, fan operation, CVT behaviour and even cabin comfort. If one goes out of range, the car can drop into failsafe and throw a warning light, or just feel a bit off.

• Engine Coolant Temperature (ECT) sensor: tells the ECM how hot the engine is to manage warm‑up enrichment, idle speed, ignition timing and radiator fan control.
• Intake Air Temperature (IAT) sensor: usually integrated with the MAF on the 2.5i, helps calculate fuel delivery and knock control.
• Ambient Air Temperature sensor: sits near the grille, informs the outside temp display and A/C logic.
• CVT Fluid Temperature sensor: inside the Lineartronic CVT, used for line pressure, shift strategy and protection.
• A/C Evaporator Temperature sensor: prevents evaporator freeze and keeps cabin temps consistent.

They’re solid‑state parts and not routine “replace by kilometre” items, but they do appreciate a bit of TLC. At service time, it’s smart to check connectors for corrosion, broken clips or chafed wiring, confirm radiator fans cycle normally, and keep the cooling system healthy with the correct coolant and a leak‑free cap. On CVT models, use the specified Subaru CVT fluid and correct level—overfilling or old fluid can skew temperature readings and upset shift quality. For the IAT/MAF, only clean with proper MAF‑safe cleaner, don’t touch the element.

• Common clues a temp sensor’s due: hard cold starts, high idle, poor economy, fans running constantly, A/C cutting in and out, or a Check Engine Light with codes like P0117/P0118 (ECT), P0113 (IAT) or P0071/P0072 (ambient).

Replacing an ECT sensor is straightforward for a trained tech: work on a cold engine, relieve pressure, expect some coolant loss, and refit with a new seal then torque to the workshop spec. Ambient sensors often get damaged in minor front knocks and are easy swaps. After any replacement, clear codes, road‑test, and confirm live data looks sensible across temperature ranges. Sticking with quality OE‑spec parts avoids odd behaviours and keeps the Outback feeling right at home on Aussie and Kiwi roads.

FAQs

Where is the engine coolant temperature sensor on a 2015 Outback?
The ECT is threaded into an engine coolant passage. On most 2.5i (FB25) it sits near the coolant crossover/thermostat area at the front of the engine, the 3.6R locates it near the thermostat housing. Access varies—some trims need intake ducting or covers removed. Always confirm exact placement in the factory manual for your engine code.

Can a bad temperature sensor cause the radiator fans to run all the time and hurt fuel economy?
Yes. If the ECT fails or reads unrealistically hot/cold, the ECM can command constant fan operation and default to rich fuelling to protect the engine. That can mean higher consumption, rough running and a Check Engine Light. A quick scan of live data usually exposes an out‑of‑range reading.

Does the CVT have a temperature sensor, and should it be replaced during a fluid change?
It does, and it’s internal to the transmission. It’s not a routine service item and isn’t replaced during fluid changes. Keep the CVT happy by using the correct Subaru CVT fluid, maintaining the cooling system, and addressing any CVT temperature‑related fault codes promptly.