P0117 on Lexus RX
Factory diagnostic protocol and troubleshooting wire for fault code P0117 specifically for the Lexus RX (2020–2026, 2.4L Turbo (RX 350 275HP) / 2.5L Hybrid / 2.4L Turbo Performance Hybrid (RX 500h 366HP)).
1. Symptoms of P0117 on Lexus RX
When the Engine Control Module (ECM/PCM) on your Lexus RX (2.4L Turbo (RX 350 275HP) / 2.5L Hybrid / 2.4L Turbo Performance Hybrid (RX 500h 366HP)) logs fault code P0117, drivers commonly observe:
2. Most Likely Causes on Lexus RX
Historical warranty claims and technical repair bulletins for Lexus RX point to the following failure distribution:
3. Step-by-Step DIY Repair Guide for Lexus RX
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 Lexus RX equipped with 2.4L Turbo (RX 350 275HP) / 2.5L Hybrid / 2.4L Turbo Performance Hybrid (RX 500h 366HP).
Unplug sensor connector while watching live data. If temperature drops to -40°F (-40°C), the sensor itself is shorted. on the Lexus RX equipped with 2.4L Turbo (RX 350 275HP) / 2.5L Hybrid / 2.4L Turbo Performance Hybrid (RX 500h 366HP).
If reading stays pegged at max with sensor unplugged, inspect harness for pinch points grounding against engine block. on the Lexus RX equipped with 2.4L Turbo (RX 350 275HP) / 2.5L Hybrid / 2.4L Turbo Performance Hybrid (RX 500h 366HP).
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 Lexus RX equipped with 2.4L Turbo (RX 350 275HP) / 2.5L Hybrid / 2.4L Turbo Performance Hybrid (RX 500h 366HP).
Bleed air from cooling system, clear DTCs, and verify normal temperature rise on live data. on the Lexus RX equipped with 2.4L Turbo (RX 350 275HP) / 2.5L Hybrid / 2.4L Turbo Performance Hybrid (RX 500h 366HP).
Equipment for Diagnosing Lexus RX (P0117)
VVT Oil Control Solenoid Valve
Restores accurate camshaft timing and oil pressure regulation on Lexus RX.
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 Lexus RX
Frequently diagnosed powertrain, emissions, and sensor trouble codes logged on the Lexus RX:
4. Lexus RX P0117 FAQs
What causes code P0117 to trigger on a Lexus RX?
On the Lexus RX (2.4L Turbo (RX 350 275HP) / 2.5L Hybrid / 2.4L Turbo Performance Hybrid (RX 500h 366HP)), 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 Lexus RX?
On the Lexus RX, the 16-pin DLC diagnostic connector is located Driver footwell above brake pedal assembly. Plug in any standard OBD-II scanner with the ignition in the ON position to read freeze-frame parameters.
Can I safely drive my Lexus RX 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.