Parts for your 2014 Toyota Mark x-Throttle position sensors

2014 Toyota Mark X throttle-position-sensor: what it does and when to service it

Yes, the 2014 Toyota Mark X uses a throttle-position sensor (TPS). Technical sources identify it as part of Toyota’s ETCS‑i (Electronic Throttle Control System – intelligent). In the GRX130/133 series Repair Manual (SFI System, ETCS‑i) on Toyota’s service platform, the throttle body assembly contains the throttle actuator and dual throttle position sensors. Toyota’s New Car Features for the 4GR‑FSE and 2GR‑FSE engines explains the drive‑by‑wire setup using an accelerator pedal position sensor and redundant TPS signals to the ECM. Denso’s ETCS‑i system literature also outlines the integrated, non‑separable TPS design used on these engines.

On the 2014 Mark X, the TPS constantly reports the exact angle of the throttle plate, letting the ECM match air flow with fuel and ignition for smooth power, decent economy, and stable idle. Because it’s built into the throttle body, it’s not a separate bolt‑on sensor like older set‑ups, the assembly provides two TPS signals for safety and accuracy.

Common signs that the car might want attention around the throttle body/TPS include:

• Erratic idle, surging or stalling at lights
• Lazy throttle response or sudden flat spots on take‑off
• Check Engine Light with codes such as P0120–P0124 or P2135
• Higher than usual fuel use

As part of routine servicing, a gentle throttle body clean can help. Use a sensor‑safe throttle cleaner and avoid forcing the plate open by hand. If the battery has been disconnected or the throttle body cleaned, let the engine warm to operating temp and idle for a few minutes so the ECM can relearn airflow, a scan tool adaptation procedure (Toyota’s throttle/idle learning in Techstream) is ideal.

If faults persist, remember the TPS isn’t normally serviced separately on this model—replacement is the complete throttle body. That means: confirm the fault properly (freeze‑frame data and live TPS/APP correlation), inspect wiring and connectors, then replace the assembly if confirmed faulty. Fit a new gasket, keep everything spotless, and tighten fasteners to workshop spec. After replacement, perform the throttle/idle learn and clear codes. Because the TPS is part of the throttle unit, using genuine‑quality parts and following the GRX130 repair procedure will save headaches and keep the Mark X driving sweet around town and on the open road.

FAQs

Does the 2014 Mark X actually have a throttle‑position sensor?
Yes. The GRX130 Mark X uses Toyota’s ETCS‑i drive‑by‑wire system. The throttle position sensors are integrated into the throttle body and provide the ECM with redundant throttle angle signals.

Can the TPS be replaced on its own?
On this model, the TPS isn’t a separate service part. If the sensor fails, the fix is to replace the complete throttle body assembly, then carry out the throttle/idle learning procedure with a scan tool or controlled idle relearn.

What symptoms point to a bad TPS on a Mark X?
Look for an unstable idle, hesitant acceleration, sudden surging, and a Check Engine Light. Diagnostic trouble codes like P0120–P0124 or P2135 are common clues, but always verify wiring and connector health before condemning the throttle body.