Parts for your 2009 Toyota Mark x-Throttle position sensors

2009 Toyota Mark X throttle position sensors

Yes, the 2009 Toyota Mark X uses throttle position sensors. Toyota’s ETCS-i (Electronic Throttle Control System – intelligent) fitted to the 4GR‑FSE and 2GR‑FSE engines in the GRX130 series employs two throttle position sensors built into the throttle body, along with an accelerator pedal position sensor on the pedal. This layout is detailed in Toyota’s New Car Features (NCF) documents for the 4GR‑FSE/2GR‑FSE and the GRX130 Repair Manual (Engine Control – ETCS‑i). The Toyota Electronic Parts Catalog for GRX130/GRX133 also lists the throttle body assembly with integrated sensors, and related DTCs such as P0120/P0121/P0220/P2135 appear in Toyota diagnostic sections for this model—clear indicators that TPS is present and monitored.

On the 2009 Mark X, the throttle position sensors tell the engine ECU exactly how far the throttle plate is open. Because it’s a drive‑by‑wire system, the ECU compares the pedal position to the throttle position and drives the throttle motor to hit the target opening. This keeps the car smooth to drive, trims fuel nicely, and adds fail‑safe redundancy thanks to the dual sensors.

For servicing, the TPS isn’t a separate bolt‑on like older cable-throttle Toyotas, it’s integrated into the throttle body and not adjustable. If the sensor fails, the usual fix is replacing the complete throttle body assembly. That said, plenty of drivability niggles come down to grime. It’s smart to include a throttle body clean in routine maintenance—especially if idle’s a bit lumpy or it hesitates off the line.

• Common clues of trouble: erratic idle, surging, limp mode, sluggish response, or codes like P0121/P2135. A scan of live data (VTA1/VTA2 and APP signals) helps nail it.
• Good workshop tips: disconnect the battery and remove the intake ducting, clean the throttle bore and plate gently with throttle body cleaner (don’t force the blade), refit with a fresh gasket if removed, and torque evenly.
• After work on the throttle, an idle/ETCS initialisation with Techstream or a capable scan tool is recommended so the ECU relearns the stop positions. The system is self‑calibrating—no manual TPS adjustment required.
• If replacement’s needed, go genuine or a reputable OEM‑equivalent, confirm part numbers via the Toyota EPC for your VIN, and inspect the harness/connector for corrosion or wire strain while you’re there.

Done right, throttle position feedback stays crisp, fuel economy remains tidy, and the Mark X keeps that effortless, linear feel Aussies and Kiwis expect from a well‑sorted Toyota sedan.

Popular questions

Does the 2009 Mark X have a separate TPS or is it part of the throttle body?
It’s built into the throttle body. Toyota’s ETCS‑i design uses dual throttle position sensors inside the throttle actuator assembly, so there’s no external, adjustable TPS like older cable‑throttle setups. If a sensor fails, the usual remedy is replacing the entire throttle body unit.

What symptoms point to a bad throttle position sensor on a 2009 Mark X?
Look for erratic idle, hesitation, poor fuel economy, limp‑home behaviour, or the MIL on. Scan for codes such as P0120/P0121/P0220/P2135 and check live data for inconsistent VTA1/VTA2 readings. Always rule out a dirty throttle bore or wiring issues before calling the sensor.

Do you need to perform a relearn after cleaning or replacing the throttle body?
Yes—an ETCS/throttle initialisation with Techstream or a capable scan tool is recommended. This lets the ECU relearn throttle stop positions and idle air control, helping avoid high idle, stalling, or sluggish response after service.