Parts for your 2009 Lexus Is-Throttle position sensors

2009 Lexus IS throttle-position-sensors: fitted, what they do, and how to look after them

Technical sources confirm the 2009 Lexus IS range (including IS 250, IS 350 and IS F) does use a throttle-position sensor. Lexus’ factory Repair Manual for the XE20 platform describes an ETCS‑i (Electronic Throttle Control System – intelligent) throttle body containing the motor and dual throttle position sensing elements, the Lexus Electronic Parts Catalogue lists the throttle body assembly with an integrated “sensor, throttle position”, and the diagnostic section details TPS‑related DTCs (such as P0120–P0124, P0220–P0223, P2135). So, the TPS is both relevant and fitted—integrated into the throttle body rather than a separate, adjustable part.

On the 2009 Lexus IS, the throttle-position sensor tells the engine control module exactly where the throttle plate sits, so fuelling, ignition timing and idle speed targets are spot on. It also feeds data to cruise control, traction and stability systems, and influences automatic transmission shift behaviour. Because the IS uses drive‑by‑wire, accuracy and redundancy are built in: the throttle body houses the motor and paired sensors, while the accelerator pedal has its own position sensors for cross‑checking.

Servicing-wise, the TPS isn’t a stand‑alone, tweakable unit. If the sensor data is erratic or out of correlation, the fix is typically to replace the complete throttle body assembly. After replacement, a throttle/idle learning procedure is required using a suitable scan tool (Lexus Techstream or equivalent) to initialise ETCS‑i and, where applicable, perform accelerator pedal zero‑point calibration. Skipping this can leave the car idling rough or dropping into limp mode.

Preventative care helps the TPS live a long life. Periodically (around every 60,000–80,000 kilometres), have the throttle body inspected and, if needed, gently cleaned with throttle‑safe cleaner. Avoid drowning the electronics or scrubbing off any protective bore coating, use a lint‑free cloth and keep solvents away from the external motor housing and connector. Check the throttle body gasket for flattening, ensure the harness plug is clean and tensioned, and never force the throttle plate open by hand under the bonnet—use the scan tool’s active test instead.

Common clues of trouble include a Check Engine light, VSC/TRC warnings, harsh idle, hesitation, stalling, poor fuel economy, or the car defaulting to limited power. Stored codes like P0120–P0124, P0220–P0223 or P2135 are good reasons to run the ETCS‑i diagnostics before calling the throttle body assembly.

Does the 2009 Lexus IS have a separate, replaceable TPS?
No. On this model the throttle-position sensing is built into the electronic throttle body with the motor. If the sensor fails or correlation codes persist, the whole throttle body assembly is replaced, followed by ETCS‑i initialisation with a scan tool.

What symptoms point to a TPS issue on a 2009 Lexus IS?
Owners may see a Check Engine light, VSC/TRC warnings, limp mode, rough idle, surging, hesitation off the line, or poor shifts. Diagnostic trouble codes such as P0120–P0124, P0220–P0223 or P2135 often appear and should be investigated before parts are ordered.

Can cleaning fix TPS‑related faults on this car?
If the problem is minor contamination of the throttle bore, a careful clean can stabilise idle and response. However, correlation or range/performance codes that return after clearing usually indicate internal sensor wear or motor issues, calling for a new throttle body and post‑install calibration.