Parts for your 2007 Toyota Mark x-Throttle position sensors

2007 Toyota Mark X throttle-position-sensors: what they do and when to service them

Based on Toyota service literature for the GRX12‑series Mark X (ETCS‑i system description) and parts catalogue listings, the 2007 Toyota Mark X absolutely uses throttle-position-sensors. They’re not a separate bolt-on sensor though — they’re built into the electronic throttle body as dual tracks (often called Throttle Valve Position Sensor No.1 and No.2). The Toyota throttle body assembly (commonly listed under 22030‑3xxxx part numbers for 4GR‑FSE/3GR‑FSE) includes the throttle motor and these sensors. So, throttle-position-sensors are relevant to this model, but they’re serviced by working with the throttle body assembly rather than as a stand-alone sensor.

On a 2007 Mark X, the throttle-position-sensors tell the engine ECU exactly how far the throttle plate is open. Paired with the accelerator pedal sensor, they let ETCS‑i manage idle quality, tip‑in response, cruise control, and traction/stability logic. Toyota uses two TPS signals so the ECU can cross‑check for accuracy and fail safe if one goes out of range.

Owners typically notice TPS‑related issues as erratic idle, flat spots on acceleration, poor fuel economy, or a Check Engine light. Common fault codes include P0121–P0123 and P2135, actuator codes like P2102 can also show up if the throttle body has trouble moving.

Because the throttle-position-sensors are integrated, replacement usually means fitting a complete throttle body assembly. For a 2007‑Toyota‑Mark‑X, it’s best to use a quality OEM unit matched to the engine (4GR‑FSE or 3GR‑FSE), along with a new gasket. These throttle bodies are coolant‑heated on the GR engines, so be ready to clamp hoses, top up coolant, and bleed the system. After installation, perform an ETCS‑i/idle relearn with a capable scan tool, a quick battery reset won’t reliably set the base idle on these.

• Don’t force the throttle plate by hand — it can damage the gears and the sensors.
• If cleaning, use throttle‑body safe cleaner sparingly and keep spray away from the motor/sensor module.
• Check the connector and wiring for corrosion or broken pins before condemning the body.
• If the plate is heavily coked up, a gentle clean and fresh gasket can restore stable idle.

As part of routine servicing of your 2007‑Toyota‑Mark‑X throttle-position-sensors, a periodic throttle bore inspection/clean, connector check, and scan for pending codes is a smart move. If faults persist or dual‑track correlation fails, replacement of the throttle body is the reliable fix, followed by a proper relearn so the ECU knows its new “home” positions.

Does a 2007 Toyota Mark X have a separate throttle-position-sensor I can swap?

No. On the GRX12‑series Mark X the throttle-position-sensors are built into the electronic throttle body as two tracks. They’re not designed to be replaced on their own, so the usual remedy is a complete throttle body assembly.

Do I need to program anything after replacing the throttle body on my Mark X?

Yes. ETCS‑i needs a throttle/idle learn so the ECU stores the new plate end‑stops and idle air targets. A proper scan tool procedure is preferred, some self‑learns by driving can work, but results are less consistent.

What are the tell‑tale signs my Mark X throttle-position-sensors are on the way out?

Hesitation on light throttle, hunting idle, sudden limp mode, and codes like P0121–P0123 or P2135 are common. If cleaning the bore and checking wiring doesn’t sort it, the internal sensor tracks may be worn and the throttle body likely needs replacement.