Parts for your 2009 Subaru Exiga-Throttle position sensors

2009 Subaru Exiga throttle position sensor: what it does and how to look after it

Based on technical references including the Subaru Exiga (YA-series) Service Manual (Engine/Diagnostics section covering DTCs P0120–P0123 and P2135) and the Subaru FAST parts catalogue for the YA-series, the 2009 Subaru Exiga is fitted with an electronic throttle body that incorporates dual throttle position sensors (TPS). Aftermarket OE-supplier catalogues for the Exiga’s EJ20-equipped throttle body also note the TPS is built into the assembly and isn’t typically serviced separately.

On a 2009 Subaru Exiga, the throttle position sensors tell the engine control module exactly how far the throttle plate is open. In this drive-by-wire setup, the TPS works alongside the accelerator pedal sensor, so the ECU can smoothly control the throttle motor and keep the car responsive and economical. It’s crucial for fuel delivery, ignition timing, idle stability, cruise control and even traction systems. The Exiga’s throttle body uses two TPS tracks for redundancy, which the ECU constantly cross-checks for safety.

While the TPS isn’t a scheduled replacement item, it benefits from sensible servicing. Under the bonnet, a periodic clean of the throttle body (every 60–100,000 kilometres or if idle gets a bit grumpy) with a proper throttle-body-safe cleaner helps keep the plate and bore free of gum that can affect sensor readings and throttle movement. Don’t force the electronic throttle plate by hand—use the accelerator or a scan tool to command it open, and keep solvents away from the motor housing and electronics.

If drivability issues show up—hesitation, hunting idle, sudden limp mode, or the MIL with codes like P0121–P0123/P2135—it’s time for diagnosis. Check for simple things first: a loose intake hose, vacuum leaks, a dirty throttle plate, or a dodgy connector. Voltage tests should show smooth, matching signals from both TPS tracks when the throttle moves. Any dropouts or mismatch will trigger a fault.

On this model, the TPS is integrated into the throttle body, so replacement usually means swapping the complete throttle body assembly. Use a new gasket, torque the fasteners correctly, and perform the throttle/idle relearn with a scan tool (or the manufacturer’s key-on procedure if available) to settle the idle. Sticking with a quality OEM or OE-supplier throttle body is wise—cheap copies can cause more grief than they solve. After refit, clear codes, confirm there are no air leaks, and take a gentle road test to verify smooth response.

• Common symptoms: erratic idle, flat spots, limp mode, MIL on with TPS-related codes.
• Good habits: periodic throttle body clean, connector inspection, and proper relearn after battery or throttle work.

Popular questions about 2009 Subaru Exiga throttle position sensors

Where is the TPS on a 2009 Subaru Exiga?
The TPS is built into the electronic throttle body, mounted on the intake manifold at the front of the engine. It’s not a separate bolt-on sensor on most Exiga variants, it lives inside the throttle body housing that also contains the throttle motor.

Can the TPS be replaced on its own?
Generally, no. For the 2009 Exiga, the TPS is part of the throttle body assembly. If the sensor fails or the signals don’t track correctly, the usual fix is replacing the complete throttle body, followed by an idle/throttle relearn.

Does the TPS need adjustment?
No adjustment is needed. The ECU self-calibrates the throttle position. If battery power has been disconnected or parts were cleaned/replaced, performing the relearn procedure is the go-to step rather than trying to mechanically “set” the sensor.