Parts for your 2021 Toyota C-hr-Throttle position sensors

2021 Toyota C‑HR Throttle Position Sensor: what it does and how to look after it

Technical sources confirm the 2021 Toyota C‑HR uses a throttle position sensor (TPS) as part of Toyota’s ETCS‑i (Electronic Throttle Control System – intelligent). The Toyota Service Information (TIS) repair manual for the C‑HR (Engine/Hybrid System: Fuel Injection Control, “ETCS‑i System Description” and “Throttle Body with Motor Assembly”) specifies that the TPS is integrated into the throttle body with motor. Toyota parts catalogues list the throttle body assembly as containing dual throttle position sensors (main/sub), and the vehicle’s DTC list includes P0121–P0124 and P2135 for throttle/throttle‑pedal position correlation, all of which confirm the TPS is fitted and actively used by the ECM.

On the 2021 C‑HR, the TPS isn’t a separate bolt‑on switch like in older cars. It’s built into the electronic throttle body and continuously reports the butterfly valve angle so the engine control module can manage airflow, fuel, and ignition. In short, it’s how the car knows exactly how much air it’s letting in, delivering smooth response, stable idle, and proper emissions control.

There’s no scheduled TPS maintenance in Toyota’s service plan because the sensor is sealed inside the throttle body. Still, a bit of care goes a long way:

• Keep the intake path tidy. Replacing the air filter on time and fixing any vacuum or intake leaks helps the TPS read accurately.
• If the throttle body gets carbon build‑up, a careful clean of the bore can restore stable idle and response. Don’t force the throttle plate by hand on a drive‑by‑wire setup.
• After cleaning or replacing the throttle body, perform an idle/throttle relearn. Many C‑HRs self‑learn after key‑on/idle, a scan tool procedure may be recommended for a precise reset.

When the TPS goes out of range, the dash may light up, the engine might idle roughly, hesitate, or drop into limp mode, and codes like P0121–P0123 or P2135 may be stored. Because the TPS is integral, replacement usually means fitting a new throttle body assembly, installing a new gasket, torquing evenly, and carrying out the appropriate relearn or zero‑point calibration. Also check the TPS connector and wiring for corrosion or damage before condemning the unit—poor pin fit or water ingress can mimic sensor faults.

It’s worth noting the accelerator pedal has its own position sensor, the ECM compares the pedal and throttle signals for safety. That’s why correlation faults can trigger reduced power if either side goes off spec.

Does the 2021 Toyota C‑HR actually have a throttle position sensor?

Yes. It’s built into the electronic throttle body as part of Toyota’s ETCS‑i system. It’s not a separate, serviceable sensor, it’s an integral component of the throttle body with motor assembly.

What are common signs the TPS is playing up on a C‑HR?

Warning lights, unstable idle, hesitation, poor throttle response, or limp‑home mode are typical. Scan results may show codes like P0121–P0123 or P2135. Always check wiring/connectors and intake leaks before replacing parts.

Can the TPS be cleaned, or does the whole throttle body need replacing?

The sensor itself is sealed and can’t be cleaned. Lightly cleaning the throttle bore can help drivability if carbon build‑up is the issue. If the TPS is faulty, the fix is normally a new throttle body assembly followed by an idle/throttle relearn.