Parts for your 2011 Subaru Forester-Throttle position sensors

2011 Subaru Forester throttle position sensor (TPS) — what it does and how to look after it

Based on the 2011 Forester (SH) Factory Service Manual and Subaru technical literature, this model uses electronic throttle control with an integrated throttle position sensor. The FSM references dual TPS signals (often labelled TPS1/TPS2) within the throttle body, and includes DTCs such as P0121–P0123 and P2135 for TPS correlation. Subaru’s genuine parts catalogue for MY11 Forester lists the throttle body as a complete assembly containing the motor and sensors, with the TPS not supplied separately. The accelerator pedal module also carries its own dual position sensors. So yes, a throttle position sensor is fitted and it’s part of the electronic throttle system on the 2011 Subaru Forester.

On this Forester, the TPS constantly reports the exact angle of the throttle plate so the engine control module can match air, fuel, and ignition for smooth, efficient running. It’s crucial for crisp take-offs, steady idle, clean gear changes, and good fuel economy. Because the TPS is built into the throttle body, care during servicing is about keeping the assembly clean, the wiring sound, and the ECM happy with accurate signals.

When a TPS plays up, the car may feel doughy off the line, surge or hesitate, idle roughly, or kick on the check engine light. Scan tools commonly show faults like P0121–P0123 or P2135. Mechanics will first rule out simple things like poor battery voltage or loose grounds—both can skew sensor readings.

• Maintenance tips:
  1. At service time, inspect the throttle body for carbon build-up. Clean gently with throttle body cleaner and a lint-free cloth—don’t flood the electronics.
  2. Check the throttle body and pedal connectors for corrosion, broken tabs, or chafed looms. Reseat plugs snugly.
  3. After cleaning or replacement, carry out an throttle/idle relearn with a scan tool (Subaru Select Monitor or equivalent) to stabilise idle and response.
  4. Avoid aftermarket “spacer” gaskets or over-tightening, air leaks upset TPS readings and idle control.

Replacement on a 2011 Forester usually means swapping the complete throttle body because the TPS isn’t serviceable on its own. A new gasket, correct torque on mounting bolts, and a proper relearn are key. Many workshops also clear adaptive trims and road-test through varied loads to confirm smooth transitions. There’s no fixed replacement interval—think “condition-based”: if symptoms or fault codes point to TPS performance, test first, then replace the assembly if confirmed. Treated kindly, the factory unit typically lasts well past 200,000 kilometres.

Popular questions about 2011 Subaru Forester throttle position sensors

Is the TPS replaceable on its own?
On the 2011 Forester, the TPS is integrated into the electronic throttle body, so it’s not sold separately by Subaru. If testing confirms a TPS fault, the practical fix is replacing the complete throttle body assembly, followed by a throttle/idle relearn.

What are common signs the TPS is playing up?
Drivers often notice a hesitant launch, surging at steady speed, a hunting idle, or poor fuel economy. The check engine light may appear with codes such as P0121–P0123 or P2135. A scan and live-data check help confirm whether the fault lies with the sensor, wiring, or the throttle body itself.

Does cleaning the throttle body help?
Yes—light carbon on the throttle plate can mimic TPS issues by upsetting airflow near closed throttle. A careful clean, connector check, and a relearn frequently restore smooth idle and response. If problems persist, further diagnosis of the throttle body and wiring is warranted.