P0117 on Lexus IS
Factory diagnostic protocol and troubleshooting wire for fault code P0117 specifically for the Lexus IS (2020–2026, 2.0L Turbo / 3.5L V6 (IS 350 311HP) / 5.0L Naturally Aspirated V8 (IS 500 472HP)).
1. Symptoms of P0117 on Lexus IS
When the Engine Control Module (ECM/PCM) on your Lexus IS (2.0L Turbo / 3.5L V6 (IS 350 311HP) / 5.0L Naturally Aspirated V8 (IS 500 472HP)) logs fault code P0117, drivers commonly observe:
2. Most Likely Causes on Lexus IS
Historical warranty claims and technical repair bulletins for Lexus IS point to the following failure distribution:
3. Step-by-Step DIY Repair Guide for Lexus IS
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 IS equipped with 2.0L Turbo / 3.5L V6 (IS 350 311HP) / 5.0L Naturally Aspirated V8 (IS 500 472HP).
Unplug sensor connector while watching live data. If temperature drops to -40°F (-40°C), the sensor itself is shorted. on the Lexus IS equipped with 2.0L Turbo / 3.5L V6 (IS 350 311HP) / 5.0L Naturally Aspirated V8 (IS 500 472HP).
If reading stays pegged at max with sensor unplugged, inspect harness for pinch points grounding against engine block. on the Lexus IS equipped with 2.0L Turbo / 3.5L V6 (IS 350 311HP) / 5.0L Naturally Aspirated V8 (IS 500 472HP).
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 IS equipped with 2.0L Turbo / 3.5L V6 (IS 350 311HP) / 5.0L Naturally Aspirated V8 (IS 500 472HP).
Bleed air from cooling system, clear DTCs, and verify normal temperature rise on live data. on the Lexus IS equipped with 2.0L Turbo / 3.5L V6 (IS 350 311HP) / 5.0L Naturally Aspirated V8 (IS 500 472HP).
Equipment for Diagnosing Lexus IS (P0117)
VVT Oil Control Solenoid Valve
Restores accurate camshaft timing and oil pressure regulation on Lexus IS.
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 IS
Frequently diagnosed powertrain, emissions, and sensor trouble codes logged on the Lexus IS:
4. Lexus IS P0117 FAQs
What causes code P0117 to trigger on a Lexus IS?
On the Lexus IS (2.0L Turbo / 3.5L V6 (IS 350 311HP) / 5.0L Naturally Aspirated V8 (IS 500 472HP)), 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 IS?
On the Lexus IS, the 16-pin DLC diagnostic connector is located Driver A-pillar base kick panel. 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 IS 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.