Parts for your 2019 Toyota Mark x-Throttle position sensors

2019 Toyota Mark X throttle position sensors (TPS)

Based on Toyota technical references for the GRX130 Mark X—namely the Repair Manual SFI/ETCS‑i sections, the New Car Features documents for the 4GR‑FSE and 2GR‑FSE V6 engines, and the 2018–2019 Electrical Wiring Diagram that shows VTA1 and VTA2 TPS circuits running from the throttle body to the ECM—the 2019 Mark X is fitted with throttle position sensors. They’re dual sensors integrated into the electronic throttle body (ETCS‑i), not a separate, adjustable unit. That means TPS is absolutely relevant on this model.

The throttle position sensors on a 2019 Toyota Mark X tell the engine computer exactly where the throttle plate sits, moment to moment. With drive‑by‑wire ETCS‑i, the ECM compares the pedal position to the two TPS signals (VTA1/VTA2), then commands the throttle motor to open or close. This keeps idle stable, throttle response tidy, emissions clean, and cruise control silky. Because the TPS is built into the throttle body, it isn’t a serviceable stand‑alone part—if the sensor side fails, the complete throttle body assembly is normally replaced.

For regular servicing, there’s no fixed replacement interval. Sensible upkeep is about prevention and checks. Under the bonnet, keep the intake tract and air filter clean so dust doesn’t score the throttle bore. If a throttle clean is needed, use a compatible cleaner sparingly with the key off, and don’t force the throttle plate by hand—let the motor do the work. Inspect the throttle body connector for corrosion or a loose fit, especially after heavy rain or engine bay washing. A workshop scan tool (Toyota Techstream or equivalent) can confirm TPS health by graphing VTA1 and VTA2—both should sweep smoothly and track each other. Common fault codes when things go pear‑shaped include P0120–P0124, P0220, and P2135, often paired with limp mode, rough idle, or a hesitant take‑off.

• Replace the throttle body assembly if the TPS signals are erratic, out of correlation, or fail tests. The sensor is not adjustable.
• After replacement, carry out throttle/idle learning. The ECM will relearn over a short drive, but a scan‑tool reset yields quicker, cleaner results.
• Always fit a new throttle body gasket and torque fasteners correctly. Clear DTCs and verify stable idle and smooth throttle behaviour over a few kilometres.

Owners who stay on top of intake cleanliness and electrical integrity typically see these throttle bodies last a very long time. If the Check Engine lamp pops on and the Mark X feels flat, a quick code read and a look at live TPS data will point a technician in the right direction.

Popular questions about 2019 Toyota Mark X throttle position sensors

Does the 2019 Mark X have a separate TPS I can replace on its own?
It doesn’t. The TPS is integrated into the electronic throttle body and uses two tracks (VTA1/VTA2) for redundancy. If the sensor fails testing, workshops replace the entire throttle body assembly rather than a separate sensor.

What are the signs the TPS is playing up on a Mark X?
Typical clues include an illuminated Check Engine lamp, limp‑home behaviour, erratic idle, surging, or sluggish throttle response. Scan tools often show codes like P0121 or P2135 and reveal a jumpy or mismatched VTA1/VTA2 sweep. Cleaning the throttle can help if contamination is the culprit, but sensor faults call for a new throttle body.

Does the TPS need resetting after battery replacement or throttle cleaning?
The ECM will relearn the throttle and idle positions with normal driving, but many technicians perform an ETCS‑i/throttle learn with a scan tool to speed things up and avoid a rough idle. After any throttle body replacement, a proper learn procedure is recommended.