Parts for your 2017 Subaru Forester-Temperature sensors

2017 Subaru Forester Temperature Sensors

Referencing the Subaru Factory Service Manual for the 2017MY Forester (FB25/FA20) and Subaru TechInfo wiring diagrams, the vehicle is absolutely fitted with several temperature sensors. These include the engine coolant temperature (ECT) sensor, intake air temperature (IAT) sensing, ambient outside air temperature for the HVAC/cluster, an evaporator temperature sensor, and transmission fluid temperature sensing on Lineartronic CVT models. These factory sources also detail how these sensors feed the ECU, TCM and HVAC control modules for reliable operation and emissions compliance.

On a 2017 Forester, temperature sensors are there to keep the engine, transmission and climate control behaving as they should. The ECT sensor governs cold-start enrichment, idle speed, ignition timing and when the radiator fans kick in. IAT helps fine-tune fuel delivery. CVT fluid temperature inputs protect the transmission under load or in hot conditions. Ambient and evaporator sensors help the air-con deliver stable, comfy cabin temps and accurate readings on the dash.

In normal servicing, these sensors are largely maintenance‑free, but a bit of care goes a long way. Keeping the cooling system healthy with the correct Subaru Super Coolant, ensuring good earths and clean connectors, and avoiding coolant contamination helps sensors read accurately. If the ECT sensor is replaced, it’s smart practice to renew the sealing washer/O‑ring, fill with the correct coolant mix, bleed the system, and confirm radiator fan cut‑in using a scan tool. The CVT temperature sensing is internal and not a routine service item, issues there are diagnosed via fault codes and live data.

Common signs a temperature sensor is playing up include hard cold starts, rich running or high fuel use, radiator fans running constantly, an erratic temp gauge, air‑con dropping out, or a CVT that goes into limp mode when hot. A quick check with an OBD‑II scanner comparing ECT to ambient when the engine is stone cold is a handy first step. When replacement is needed, OE or high‑quality equivalent parts are recommended, and wiring/connector integrity should be verified before condemning the sensor.

• Engine Coolant Temperature (ECT): near the thermostat/water outlet under the bonnet.
• Intake Air Temperature (IAT): typically integrated with the MAF housing.
• CVT Fluid Temperature: internal to the transmission control assembly.
• Ambient/EVAP Temp: front grille area and HVAC case respectively.

Popular questions about 2017 Subaru Forester temperature sensors

Does the 2017 Forester actually have a coolant temperature sensor?
Yes. Factory documentation lists an engine coolant temperature sensor that the ECU relies on for warm‑up fuelling, fan control and timing. Without it, drivability and emissions suffer.

Where is the coolant temperature sensor located?
On FB‑series engines it’s mounted at the coolant outlet/thermostat housing under the bonnet. Access varies with trim and intake ducting, but it’s generally reachable with basic hand tools once the engine is cool.

Do temperature sensors need regular servicing?
They’re not a scheduled service item. The best “service” is maintaining clean electrical connections and fresh, correct coolant. Replace only if readings are implausible, fault codes are present, or diagnostics confirm a failed sensor.