Parts for your 2017 Toyota Avensis-Throttle position sensors

2017 Toyota Avensis throttle-position-sensor: what it does, where it lives, and how to look after it

Technical documentation shows the 2017 Toyota Avensis does use a throttle-position sensor (TPS). Toyota’s Avensis T27 Repair Manual for the SFI/ETCS-i system identifies “Throttle Position Sensor No.1/No.2” integrated within the Throttle Body with Motor Assembly, and the Toyota Electronic Parts Catalogue lists the throttle body assembly for the 1ZR-FAE and 2ZR-FAE petrol engines as including the TPS. The Electrical Wiring Diagram also shows dual-track TPS signals to the ECM, and the diagnostic section lists DTCs such as P0121, P0122 and P0123 for TPS range/performance and circuit faults. Diesel variants include an intake throttle valve with a built-in position sensor used for EGR control and smooth shutdown. Sources: Toyota Avensis (T27, 2015–2018) Repair Manual – Engine/Hybrid System > SFI System (ETCS-i), Toyota EWD, Toyota EPC (Throttle Body with Motor Assembly).

On the 2017 Avensis, the throttle-position sensor is a twin-track, non-contact sensor built into the electronic throttle body. Its job is simple but crucial: it tells the engine control module exactly where the throttle plate sits, so fuelling, ignition timing, idle speed and emissions gear all stay on song. Even with Valvematic petrol engines doing most of the breathing tricks via valve lift, the throttle plate still moves and still needs accurate feedback from the TPS.

Because the TPS is part of the throttle body, it isn’t serviced on its own. If the sensor fails electrically or goes out of spec, the fix is typically a replacement throttle body assembly and a new gasket. After refitting, a throttle/idle relearn or ETCS-i initialisation with a scan tool is recommended so the ECU knows the exact closed and fully open positions again. Always torque fasteners to the spec in the workshop manual and check for coolant lines or PCV hoses that may need to be transferred.

Classic TPS-related symptoms on an Avensis include harsh or hunting idle, a lazy throttle response, sudden limp-home with the MIL on, and codes like P0121–P0123. Before binning parts, it’s worth ruling out basics: a carboned-up throttle bore can stick the plate just enough to upset readings. A careful clean of the throttle body (off the car is safest) with sensor-safe cleaner often restores smooth movement. Also check the accelerator pedal position sensor harness and grounds—different sensor, similar complaints.

As part of routine servicing, a quick visual on the throttle body, a data-list glance at “Throttle Position Sensor No.1/No.2” agreement, and a light clean when deposits build up will keep things tidy. If the car’s doing big kilometres or lives around dust and short trips, that bit of preventative love pays off. And if replacement’s on the cards, go quality on the throttle body—cheapies can introduce tracking mismatches that the ECU won’t tolerate.

• Watch for TPS-related DTCs (P0121–P0123) and ETCS-i warnings
• Clean the throttle bore when deposits appear, avoid drowning the motor/sensor
• Perform throttle relearn after battery disconnect or throttle body replacement

Popular questions

Does a 2017 Avensis have a separate TPS or is it built into the throttle body?
The TPS on the 2017 Avensis is built into the electronic throttle body as a dual-track sensor. It’s not serviced separately, so faults generally mean replacing the complete throttle body assembly.

What are the tell-tale signs of a failing TPS on this model?
Expect a check engine light, limp-home, uneven idle, poor throttle response, and codes like P0121–P0123. A sticky, carboned throttle plate can mimic these, so cleaning and live-data checks are smart first steps.

After replacing the throttle body, is calibration needed?
Yes. An ETCS-i/throttle position relearn with a scan tool is recommended so the ECU records correct closed and open angles. This helps avoid high idle, stumble, or repeat fault codes.