Parts for your 2015 Subaru Xv-Temperature sensors

2015 Subaru XV temperature sensors — what they do and how to look after them

Temperature sensors absolutely are used on the 2015 Subaru XV (FB20 engine, Lineartronic CVT). Subaru’s Factory Service Manual for the XV/Crosstrek details an Engine Coolant Temperature (ECT) sensor and an Intake Air Temperature (IAT) sensor, while the CVT (TR580) section specifies a transmission fluid temperature sensor used by the TCM. The HVAC diagnostics also list evaporator and ambient air temperature sensors. These are supported by standard OBD-II diagnostics such as P0117/P0118 (ECT), P0113 (IAT) and P0711–P0713 (CVT fluid temperature), confirming they’re fitted and critical to vehicle operation.

On this XV, temperature sensors help the ECU and TCM make smart calls about fuelling, spark timing, idle speed, fan control and shift strategy, while the climate system uses them to keep the cabin comfy and prevent evaporator icing. When they go out of whack, drivers can see hard cold starts, high fuel use, odd fan behaviour, limp-home from the CVT, or air-con cutting in and out.

• Engine coolant temp (ECT): Governs warm-up enrichment, fan activation and overheat protection.
• Intake air temp (IAT, in the MAF body): Fine-tunes fuelling and timing.
• CVT fluid temp: Protects the transmission and adjusts shift/pressure strategy.
• Ambient/evaporator temp: Guides AC performance and prevents icing.

Service-wise, these sensors aren’t “consumables”, but checking them pays off. Any time the coolant is serviced, inspect the ECT connector and sealing area under the bonnet for leaks or crusty deposits, use the correct Subaru-approved long-life coolant and bleed air properly. A scan tool should show ECT and IAT close to ambient when cold (typically within a couple of degrees). If readings are miles off, test wiring and sensor resistance per the service manual.

Replacing the ECT usually means draining a little coolant, swapping the sensor and sealing washer/O-ring, then refilling and bleeding the system. Always follow the factory torque spec and avoid over-tightening. For the IAT, avoid touching the tiny thermistor, if contaminated, use MAF-safe cleaner only. The CVT fluid temperature sensor is internal, if it triggers a code, diagnosis is best left to a transmission specialist, and always use Subaru-specified CVT fluid. The front ambient sensor sits behind the grille and is easy to damage in minor front impacts—worth a quick look after a bumper repair.

1. Log live data before replacing parts.
2. Rule out wiring/connector faults.
3. Fit quality parts and clear codes, then road test to operating temperature.

Popular questions

Where is the engine coolant temperature sensor on a 2015 Subaru XV?
The ECT sensor threads into the engine coolant passage on the FB20. It’s accessed from the top of the engine bay under the bonnet, exact visibility varies with intake ducting and covers. A torch helps to spot the two-pin connector.

If removing it, be ready to catch coolant, fit a new sealing washer/O-ring, and top up with the correct coolant before bleeding the system.

What symptoms point to a bad temperature sensor on the XV?
Common signs include rich running when warm, poor cold starts, radiator fans running constantly or never coming on, a wandering temp gauge, AC cutting out, or a CVT that feels lazy when hot. Scan tool data that doesn’t match real-world temps is a giveaway.

Always confirm with wiring checks and resistance tests—don’t throw parts at it without data.

Does the XV’s CVT have a temperature sensor, and is it serviceable?
Yes, the TR580 CVT monitors fluid temperature. Faults set codes like P0711–P0713 and can force protective behaviour. The sensor is internal, so repair typically involves transmission work rather than a quick driveway swap.

Keeping the correct Subaru-specified CVT fluid in good nick and the cooler unobstructed helps prevent temperature-related issues.