Parts for your 2013 Toyota Bb-Throttle position sensors

2013 Toyota bB throttle-position-sensors (TPS): what they do and how to look after them

On the 2013 Toyota bB (QNC20/QNC21 series with K3-VE or 3SZ-VE engines), a throttle-position-sensor is absolutely used. Toyota’s factory service information and wiring diagrams for the bB show an electronic throttle body (ETCS‑i) that houses a throttle actuator motor and dual throttle-position-sensor tracks (often referenced as VTA1/VTA2). These sensors report the throttle plate angle to the engine ECU, with matching dual accelerator pedal sensors providing the driver’s request. The ECU cross-checks the signals for safety and precision. If the signals disagree or drift out of range, the ECU logs DTCs (such as P0120–P0124 or P2135) and may enter limp mode to protect the engine and occupants.

On this model, the TPS is integrated into the throttle body and is non-adjustable. Its job is to tell the ECU exactly how far open the throttle is so fuelling, ignition timing, idle control, transmission shift strategy, and cruise/traction functions can all work smoothly. A healthy TPS gives crisp throttle response, stable idle, and good fuel economy. A failing TPS (or wiring to it) can cause harsh or lazy throttle, hunting idle, stalling, poor economy, a check-engine light, and reduced power. Because the sensor is built-in, diagnosis focuses on live-data comparisons (VTA1 vs VTA2 tracking smoothly and proportionally) and circuit checks, rather than trying to “tune” the sensor.

There’s no scheduled replacement interval for the TPS on a 2013 bB, it’s replaced on condition. As part of routine servicing, it’s smart to keep the throttle body clean with an appropriate intake cleaner (don’t force the plate by hand), inspect the connector and loom for corrosion or chafing, and ensure battery voltage/ground quality is sound—ETCS‑i is fussy about supply voltage. If the TPS proves faulty, the usual repair is a complete throttle body assembly with a new gasket. After replacement—or any time the throttle body has been removed—carry out an ETCS idle/air volume learn using a capable scan tool, clear related DTCs, and road test to confirm smooth pedal-to-throttle behaviour. Stick with quality OEM-equivalent parts and tighten fasteners to the factory torque spec to avoid air leaks or warping.

Does the 2013 Toyota bB have a separate TPS or is it built into the throttle body?

It’s built into the electronic throttle body and uses dual sensor tracks. It’s non-adjustable and generally not sold separately from the throttle body assembly. Fault finding is done via scan data and electrical checks, then the assembly is replaced if confirmed faulty.

Can a dodgy TPS be fixed by cleaning, or does it need replacement?

If the problem is carbon build-up causing a sticky throttle plate, a careful clean can help. If the TPS itself is erratic or the dual tracks don’t correlate, cleaning won’t fix it—the throttle body assembly needs replacement, followed by an idle/ETCS learn.

After replacing the throttle body/TPS on a 2013 bB, is calibration needed?

Yes. Perform the ETCS idle air volume learn (zero-point/idle learn) with a suitable scan tool so the ECU knows the new sensor’s baseline. Without this step, idle quality and tip-in response can be ordinary and fault codes may return.