Parts for your 2025 Toyota Aqua-Throttle position sensors

2025 Toyota Aqua throttle-position-sensors: what they do and how to look after them

Short answer: yes, the 2025 Toyota Aqua uses throttle-position-sensors (TPS). Toyota’s electronic throttle control system (ETCS‑i) on the Aqua’s M15A‑FXE hybrid engine has dual, built‑in TPS elements inside the electronic throttle body. This is documented in Toyota’s New Car Features (NCF) for the Aqua/Yaris Hybrid (M15A‑FXE) under ETCS‑i, and in the Toyota Repair Manual (SFI: Throttle Body with Motor and Throttle Position Sensor, Diagnostics for DTCs P0121–P0123, P0222–P0223). Toyota technical training materials for ETCS‑i also detail the use of redundant TPS signals and correlation checks via Techstream.

On the 2025 Aqua, the TPS constantly reports the throttle plate angle to the engine ECU. That data lets the hybrid system blend engine torque with electric drive smoothly, manage idle airflow when the engine kicks in under the bonnet, and keep emissions tidy. There are two sensor tracks for redundancy: if one goes walkabout, the ECU compares signals and throws a fault rather than risking a sticky throttle. It’s different to the accelerator pedal position sensor (that’s at the pedal), the TPS lives in the throttle body and monitors the actual blade position.

There’s no scheduled replacement interval for the throttle-position-sensors on this model. They’re sealed into the electronic throttle body, so if a TPS fails, the fix is usually a complete throttle body assembly. Typical tell‑tales include a check engine light, sluggish pick‑up, hunting idle when the engine starts, or poor fuel economy. Common codes you might see are P0121–P0123 or P0222–P0223. A quick scan with Techstream or an OBD‑II tool to check live data (throttle angle vs commanded) is the smart first step.

Good servicing practice for the Aqua includes periodically cleaning the throttle bore and blade with an appropriate throttle cleaner, taking care not to flood the electronics. Avoid poking at the throttle plate by hand with the key on. If the throttle body is replaced, use a new gasket, check for vacuum leaks, and carry out the ETCS‑i throttle/idle learning procedure with a scan tool. After battery disconnection or replacement, the ECU may relearn over a short drive, but a guided reset is tidier.

• Symptoms that warrant attention: erratic idle when the engine engages, reduced power, higher fuel use, MIL on with TPS-related DTCs.
• DIY tip: disconnect the 12‑V negative terminal before unplugging the throttle body. There’s no need to touch the high‑voltage hybrid system for this job.

Technical sources referenced: Toyota New Car Features (Aqua/Yaris Hybrid, M15A‑FXE, ETCS‑i), Toyota Repair Manual (SFI: Throttle Body with Motor and Throttle Position Sensor, DTC P0121–P0123, P0222–P0223 diagnostics, throttle learning procedure), Toyota ETCS‑i Technical Training.

FAQs

Does the 2025 Toyota Aqua actually have a throttle-position-sensor?
Yes. The Aqua’s electronic throttle body contains dual throttle-position-sensors as part of Toyota’s ETCS‑i. They monitor the throttle blade angle so the ECU can control airflow precisely during hybrid engine start/stop and acceleration.

Can the TPS be cleaned or repaired, or does it need replacing?
The TPS is integrated into the throttle body and isn’t serviceable on its own. You can clean the throttle bore and blade to fix minor sticking or idle issues, but an internal TPS fault usually means replacing the complete throttle body and performing a throttle/idle learn with a scan tool.

What fault codes point to a TPS issue on a 2025 Aqua?
Typical codes include P0121–P0123 and P0222–P0223, often flagged when the two internal TPS signals don’t agree or don’t track commanded throttle. If these appear with poor driveability, check live data and wiring before condemning the throttle body.