Parts for your 2006 Toyota Mark x-Throttle position sensors

2006 Toyota Mark X throttle position sensor (TPS) — what it is and how it’s handled

Yes, the 2006 Toyota Mark X uses a throttle position sensor, and it’s relevant to both drivability and diagnostics. Toyota’s New Car Features for the GR-series engines and the GRX120/121 Repair Manual (Engine Control – SFI/ETCS-i) describe an electronic throttle (ETCS‑i) system on the 3GR‑FSE and 4GR‑FSE engines. In this setup the throttle body contains a throttle control motor and a dual‑track throttle position sensor (often labelled VTA1/VTA2) feeding the ECM. The Mark X’s Electrical Wiring Diagram shows these VTA circuits, and related diagnostic trouble codes (such as P0120–P0124 and P0220–P0222) are documented in Toyota service literature. Toyota’s electronic parts catalog also lists the throttle body assembly as “with motor & sensor,” which indicates the TPS is integrated and generally not sold separately. So, the TPS is very much part of the 2006 Mark X, just packaged within the throttle body.

The throttle position sensor on a 2006 Mark X tells the engine computer exactly how far the throttle plate is open. That live angle data gets used for fueling, ignition timing, idle speed control, transmission shift strategy and even traction and stability systems. On the GR‑series V6 with D‑4 direct injection and Dual VVT‑i, accurate throttle feedback helps keep idle smooth, tip‑in crisp, and cruise nice and steady without the surging that can drive anyone spare on a long Kiwi motorway or Aussie freeway.

There’s no scheduled replacement for the TPS because it’s sealed inside the throttle body. The smart play during regular servicing is: keep the throttle bore clean, but don’t drown the shaft area with harsh solvent, check for stored fault codes, and make sure battery voltage and grounds are healthy. If the sensor goes out of range or develops a dead spot, expect symptoms like erratic idle, sudden limp mode, poor off‑the‑line response, or the MIL/traction lights coming on. A scan tool should show two smooth, matching throttle angle signals that rise evenly with pedal movement, any flat spots or mismatch will give the game away.

When a TPS fault is confirmed, the fix on a Mark X is typically a complete throttle body assembly. Fit a new gasket, torque the fasteners evenly, and inspect the PCV and coolant hoses while there. After replacement—or any major clean or battery reset—perform the ETCS‑i/throttle learning procedure using Toyota Techstream or the workshop’s approved method so the idle and throttle control relearn correctly. As a preventative, many techs like to clean the throttle body every 60,000–100,000 km and check live data, it’s quick insurance that keeps the V6 feeling sharp and drama‑free.

• Common TPS-related symptoms: rough idle, hesitation, limp mode, increased fuel use, MIL with P012x/P022x codes.
• Service tip: clean throttle bore carefully, avoid soaking sensors, and run a throttle relearn when needed.
• Replacement note: TPS is integrated, replace the throttle body if the sensor is faulty.

Popular questions

Does the 2006 Toyota Mark X actually have a TPS?
It does. The Mark X uses an electronic throttle (ETCS‑i), and the throttle position sensor is built into the throttle body alongside the throttle motor. Toyota’s factory manuals and wiring diagrams list the dual throttle angle signals the ECM relies on for smooth control.

Can the TPS be replaced on its own, or is it part of the throttle body?
On this model it’s part of the throttle body assembly and isn’t normally sold separately. If testing shows the TPS is faulty, the recommended repair is to replace the complete throttle body, fit a new gasket and carry out throttle/idle learning.

How do you tell if the TPS is on the way out?
Watch for a rough or wandering idle, flat spots on acceleration, unexpected limp mode and fault codes like P0120–P0124. A scan tool check should show smooth, matching throttle angle signals, any spikes or dropouts under slow throttle movement point to a bad sensor or wiring issue.