Parts for your 2008 Subaru Exiga-Throttle position sensors

2008 Subaru Exiga throttle-position-sensors: what they do and how to look after them

Yes, the 2008 Subaru Exiga uses throttle-position-sensors. Subaru’s factory service information for the YA-series Exiga (EJ20 engines, 2008 MY) describes an electronic throttle body with a motor and two throttle position sensors (TPS1/TPS2) for redundancy, along with an accelerator pedal position sensor. This setup is part of Subaru’s electronic throttle control. Typical diagnostic references in the same manuals list related OBD-II codes such as P0121–P0123 and P2135, confirming the TPS is a monitored, serviceable item.

On this Exiga, the throttle-position-sensors are built into the throttle body. Their job is straightforward: report the exact angle of the throttle plate to the engine control unit so fuelling, ignition, and idle control stay smooth and efficient. With drive-by-wire, the ECU compares pedal input with the throttle plate’s actual position using the twin sensors, keeping things safe and responsive.

When the TPS goes out of range or the signals don’t agree, the car can drop into limp mode, idle roughly, surge, hesitate, or light the check engine lamp. It’s not a routine replacement item, but it’s definitely one to keep on the radar during servicing.

• Symptoms to watch for:
  • Hunting or stalling at idle
  • Flat spots or jerky throttle
  • Poor fuel economy
  • Check engine light with TPS or throttle/pedal correlation codes

1. Service tips:
   • Scan for codes and live data. Look for smooth, consistent throttle angle readings that track pedal input.
   • Inspect the connector and loom near the throttle body for corrosion or broken wires—common culprits before the sensor itself.
   • Clean the throttle bore and plate with throttle-body-safe cleaner. Avoid soaking the motor housing or the sensor area and don’t force the plate by hand.
   • If replacement is needed, fit a quality throttle body assembly (the TPS is integral). Renew the gasket, observe torque specs, and perform idle/ETC relearn with a scan tool (Subaru Select Monitor or equivalent).
   • After battery disconnection or cleaning, allow the ECU to relearn idle—let it idle without loads until stable, then drive a few kilometres with varied throttle.

With the right checks and a gentle clean during scheduled servicing, most Exiga owners won’t need to replace the throttle-position-sensors for many years. But if the warning light’s on and it feels a bit off underfoot, a proper scan and throttle-body inspection are the first ports of call.

Popular questions about 2008 Subaru Exiga throttle-position-sensors

How do you tell if the TPS is the problem or the accelerator pedal sensor?
Both can cause hesitation or limp mode. A scan tool helps separate them: if the accelerator pedal position tracks smoothly but the throttle position is erratic, suspect the TPS/throttle body. If both pedal signals are jumpy from the start, the pedal sensor or its wiring may be at fault. Correlation codes like P2135 often appear when the two don’t agree.

Do you need to program anything after replacing the throttle body on an Exiga?
There’s no coding of the sensor itself, but an idle/throttle relearn is recommended. Using a suitable scan tool to run the ETC or idle learning routine is best. If that’s not available, a manual relearn (key on, wait, then idle with all loads off, followed by a short drive cycle) usually settles it.

Can cleaning fix TPS-related issues?
If the issue is from a sticky throttle plate or carbon build-up, a careful clean can restore normal readings. If the sensor’s internal tracks are worn or signals are inconsistent despite a clean and sound wiring, replacement of the throttle body assembly is the reliable fix.