Parts for your 2015 Lexus Is-Throttle position sensors

2015 Lexus IS throttle position sensors (TPS)

Technical sources confirm the 2015 Lexus IS uses throttle position sensors. The Lexus Technical Information System (TIS) factory repair manual for GSE3# IS models (4GR-FSE/2GR-FSE) in the SFI and ETCS‑i sections lists a “Throttle Position Sensor (built into throttle body)” with dual circuits (VTA1/VTA2), and includes diagnostics for DTCs P0120–P0124 and P0220–P0224. Lexus wiring diagrams and the Lexus/Toyota Electronic Parts Catalogue also show the TPS integrated into the motorised throttle body, with the accelerator pedal carrying its own dual position sensors. That’s clear evidence the 2015 IS is fitted with TPS as part of Toyota’s ETCS‑i (drive‑by‑wire) system.

For the 2015 Lexus IS, the throttle position sensors are the throttle body’s way of telling the engine computer exactly where the butterfly plate is, in real time. In a drive‑by‑wire setup like ETCS‑i, the ECU compares the driver’s accelerator pedal request with actual throttle plate angle from the TPS to control torque, fuel and ignition, idle speed, cruise control, transmission shift timing and even traction and stability systems. Using dual TPS tracks adds redundancy and safety, if the signals don’t agree, the car can drop into limp mode to protect the engine and occupants.

There’s no scheduled replacement for the TPS on this model because it’s integrated into the electronic throttle body and designed to be maintenance‑free. That said, good servicing habits go a long way:

• Keep the throttle body clean. A careful clean of the bore and plate (without forcing the plate by hand) helps stable idle and crisp response.
• Inspect the connector and loom for oil ingress, corrosion or bent pins, especially if the vehicle sees lots of heat or road grime.
• After cleaning or battery disconnect, perform an idle/throttle learn with a scan tool as per the factory procedure so the ECU relearns the plate position.

Common clues the TPS/throttle body needs attention include a check engine light with TPS‑related DTCs, erratic idle, hesitation, surging, poor fuel economy, harsh or odd shifts, and reduced‑power (limp) behaviour. If diagnostics point to the TPS, the fix on most 2015 IS variants is to replace the throttle body assembly (the sensor isn’t typically serviceable on its own). Use a new gasket, don’t overtighten the fasteners, and reconnect any coolant lines if fitted. Finish with a proper throttle/idle relearn, clear codes, and verify live data shows smooth, linear throttle angle from closed to wide open. Choosing an OE or high‑quality throttle body avoids calibration headaches and ensures the dual‑track sensor data stays spot on.

Look after the throttle body and its sensors, and the 2015 IS will reward with silky response, tidy fuel use and that characteristically smooth Lexus drivability.

Does a 2015 Lexus IS have a throttle position sensor?
Yes. The 2015 IS uses Toyota’s ETCS‑i drive‑by‑wire system with dual throttle position sensors built into the electronic throttle body, plus dual accelerator pedal position sensors on the pedal.

Can the TPS be replaced separately from the throttle body?
On most 2015 IS variants, no. The TPS is integrated into the throttle body and isn’t serviced on its own. If the TPS fails testing, the usual repair is a complete throttle body replacement with a new gasket and an ECU relearn.

What are the signs the TPS/throttle body needs attention?
Check engine light with TPS codes, rough or wandering idle, hesitation, flat‑spots, poor economy, unexpected transmission shift behaviour and limp‑mode. Always confirm with scan‑tool data and factory test procedures before replacing parts.