Parts for your 2023 Subaru Impreza-Throttle position sensors

2023 Subaru Impreza throttle position sensors (TPS): what they do and how to look after them

Yes — a throttle position sensor is used on the 2023 Subaru Impreza. Subaru’s factory service information (STIS) for the 2017–2023 Impreza with the FB-series engine describes an electronic throttle control system featuring an electronic throttle body with dual throttle position sensors (TPS1/TPS2) and dual accelerator pedal position sensors. The same sources list relevant OBD-II fault codes (e.g., P0120, P0121, P0122, P0123, P0220, P2135) tied to throttle/pedal position signals. Subaru parts catalogues also show the throttle body supplied as an assembly with the TPS integrated and non-adjustable.

The TPS on a 2023 Impreza tells the engine control module exactly how far the throttle plate is open. Because it’s a drive-by-wire setup, there’s no cable under the bonnet — the ECU reads the accelerator pedal sensors, cross-checks the TPS signals in the throttle body, and commands the motor to open or close the plate. That keeps idle stable, helps fuel economy, smooths gear changes in autos, and integrates with traction and cruise control. Subaru uses two TPS signals for redundancy and correlation, which is why mismatches typically trigger a check-engine light and limp mode instead of letting things run unpredictably.

Under normal servicing, there’s no scheduled replacement for the TPS because it’s sealed inside the throttle body. What does help is keeping the throttle bore clean. If idle turns rough or the car hunts at a stop, a careful clean of the throttle body with appropriate cleaner can restore smooth airflow. Don’t force the plate open, let the motor move it, and avoid soaking the electronics. After battery disconnection or throttle body work, the ECU will generally relearn idle over a short drive, but a scan tool can run an electronic throttle relearn if needed.

Suspect a TPS issue? Typical signs include erratic idle, sudden loss of power, delayed throttle response, poor fuel economy, and a check-engine light with codes like P0121 or P2135. Because the TPS is not serviceable separately on this model, confirmed TPS faults usually mean replacing the complete throttle body assembly. Use a new gasket, check for vacuum leaks, and verify the two TPS signals track smoothly and agree in live data. If you’re chasing intermittent faults, gently wiggle the harness with the engine running and watch for signal dropouts in scan data — wiring strain at the connector can mimic a bad sensor.

• Keep the intake tract and air filter in good nick to prevent contamination.
• Scan first, replace last: confirm DTCs and correlation before ordering parts.
• After replacement, perform an idle/throttle relearn and clear codes.

Popular questions

Does the 2023 Impreza have both a throttle position sensor and a pedal sensor?
Yes. The electronic throttle body has two internal TPS circuits, and the accelerator pedal has its own dual position sensors. The ECU compares them for accuracy and safety, which is why mismatch codes can put the car into limp mode to protect the engine.

Can the TPS on a 2023 Impreza be replaced on its own?
No. On this model the TPS is integrated into the throttle body and isn’t adjustable or serviced separately. If the TPS is confirmed faulty, the fix is to replace the throttle body assembly, fit a new gasket, and carry out an idle/throttle relearn.

What are the common symptoms of a failing TPS on this car?
Owners usually notice an unstable idle, flat spots on acceleration, reduced power, or the check-engine light. Scan tools often show codes such as P0121 or P2135 and reveal that the two TPS signals don’t agree or aren’t smooth as the throttle moves.