Parts for your 2020 Mazda 3-Throttle position sensors

2020 Mazda 3 throttle position sensor (TPS): purpose, faults and servicing advice

Based on Mazda’s BP-platform Workshop Manual for the 2019–2021 Mazda3 (Engine Control System, Electronic Throttle Control) and its wiring diagrams, the 2020 Mazda 3 runs an electronic throttle body with an integrated, dual-track throttle position sensor (often labelled TP1/TP2) feeding the PCM. The related OEM diagnostic sections for DTCs such as P0121, P0221 and P2135 also confirm the system monitors two throttle-angle signals for correlation. This means a throttle position sensor is absolutely used on the 2020 Mazda 3, it’s built into the throttle body and is not a separate, adjustable part.

On the 2020 Mazda 3, the TPS is a key part of the drive-by-wire setup. It tells the computer the exact angle of the throttle plate so fuelling, ignition and transmission behaviour stay crisp and consistent. The unit uses two tracks for redundancy: the PCM constantly checks that both signals agree, so if one goes wonky, it can catch it quickly and protect the engine with a limp-mode strategy.

Because the TPS is built into the throttle body assembly, it isn’t a routine service item and it can’t be tweaked. If the sensor fails, the proper fix is to replace the throttle body as a unit, then carry out the throttle/idle learn procedure with a scan tool so the PCM knows the new “fully closed” and “fully open” positions. Most owners will only ever interact with it indirectly—through regular servicing that keeps the throttle body clean and the electrical connections healthy.

• Common symptoms when the TPS or its circuit plays up: uneven idle, hesitation off the line, surging, reduced power/limp mode, and a Check Engine Light with codes like P0121, P0122, P0221 or P2135.
• Good maintenance practice: during scheduled services (every 10,000–15,000 km), have the intake inspected for leaks, the throttle body bore and plate checked for deposits, and the TPS connector and harness looked over for corrosion or strain. Use throttle-body-safe cleaner only—don’t drown the electronics—and avoid forcing the plate by hand.
• Diagnosis tips for workshops: view live data for TP1/TP2 and accelerator pedal signals for a smooth, matching sweep, confirm stable battery voltage, and rule out earthing issues. If signals drop out or the two throttle tracks don’t correlate within spec, replacement of the throttle body is the OEM path.
• Replacement pointers: fit a new gasket, torque evenly, clear DTCs, and perform throttle/idle relearn. A brief idle hunt after battery disconnection or cleaning is normal until the PCM relearns.

Looked after properly, the factory throttle body and its TPS can go the distance for many years and many kilometres. Keeping the intake clean and the electrics sound pays off with smooth response and solid economy from the Skyactiv-G.

Does the 2020 Mazda 3 have a throttle position sensor?
Yes. The BP-series Mazda 3 uses an electronic throttle body with a built-in, dual-track throttle position sensor that reports throttle angle to the PCM for precise control.

Can the TPS be replaced on its own, or is it part of the throttle body?
On this model it’s integrated into the throttle body and isn’t serviceable separately in OEM practice. If the TPS fails testing, the throttle body assembly is replaced and a throttle/idle relearn is carried out.

What are the tell-tale signs of a failing TPS on a 2020 Mazda 3?
Owners may notice a Check Engine Light, sluggish throttle response, unstable idle, or limp-home behaviour. Scan tools often show codes like P0121, P0221 or P2135, and live data reveals noisy or mismatched TP signals.