P0117 on Subaru Forester
Factory diagnostic protocol and troubleshooting wire for fault code P0117 specifically for the Subaru Forester (2020–2026, 2.5L Direct Injection Boxer-4 (182HP / Symmetrical AWD)).
1. Symptoms of P0117 on Subaru Forester
When the Engine Control Module (ECM/PCM) on your Subaru Forester (2.5L Direct Injection Boxer-4 (182HP / Symmetrical AWD)) logs fault code P0117, drivers commonly observe:
2. Most Likely Causes on Subaru Forester
Historical warranty claims and technical repair bulletins for Subaru Forester point to the following failure distribution:
3. Step-by-Step DIY Repair Guide for Subaru Forester
Read ECT live PID on scanner. If it reads 284°F (140°C) or higher with engine cold, a short to ground exists. on the Subaru Forester equipped with 2.5L Direct Injection Boxer-4 (182HP / Symmetrical AWD).
Unplug sensor connector while watching live data. If temperature drops to -40°F (-40°C), the sensor itself is shorted. on the Subaru Forester equipped with 2.5L Direct Injection Boxer-4 (182HP / Symmetrical AWD).
If reading stays pegged at max with sensor unplugged, inspect harness for pinch points grounding against engine block. on the Subaru Forester equipped with 2.5L Direct Injection Boxer-4 (182HP / Symmetrical AWD).
Allow engine to cool, unscrew old ECT sensor from coolant crossover pipe or thermostat housing, install new OEM sensor with fresh thread sealant. on the Subaru Forester equipped with 2.5L Direct Injection Boxer-4 (182HP / Symmetrical AWD).
Bleed air from cooling system, clear DTCs, and verify normal temperature rise on live data. on the Subaru Forester equipped with 2.5L Direct Injection Boxer-4 (182HP / Symmetrical AWD).
Equipment for Diagnosing Subaru Forester (P0117)
VVT Oil Control Solenoid Valve
Restores accurate camshaft timing and oil pressure regulation on Subaru Forester.
AstroAI Auto-Ranging Digital Multimeter
Essential for testing 0.1V–5.0V sensor reference signals, ground continuity (<0.20Ω), and harness resistance.
BlueDriver Bluetooth Pro OBDII Scan Tool
Reads and clears enhanced codes (ABS, Airbag, Transmission, Engine) & live freeze-frame telemetry on phone.
Other Common Fault Codes on Subaru Forester
Frequently diagnosed powertrain, emissions, and sensor trouble codes logged on the Subaru Forester:
4. Subaru Forester P0117 FAQs
What causes code P0117 to trigger on a Subaru Forester?
On the Subaru Forester (2.5L Direct Injection Boxer-4 (182HP / Symmetrical AWD)), P0117 is most frequently caused by ECT sensor internal short to ground or Short circuit to ground in ECT signal wiring harness.
Where is the OBD-II port located on my Subaru Forester?
On the Subaru Forester, the 16-pin DLC diagnostic connector is located Driver lower dash panel near hood lever. Plug in any standard OBD-II scanner with the ignition in the ON position to read freeze-frame parameters.
Can I safely drive my Subaru Forester with code P0117?
No. The ECU thinks the engine is at 280°F+ (overheating) and runs rich or disables cooling fan logic. Given that P0117 carries a High severity rating, we advise avoiding heavy towing or aggressive throttle inputs until sensor readings are verified.