Standard Ignition TH389 Throttle Position Sensor

Throttle Position Sensor for Subaru Applications

Standard Ignition TH389 is a throttle position sensor for select Subaru vehicles, including Impreza, Forester, Legacy, Outback, and Baja applications. It provides the throttle position signal used by the engine control system to monitor throttle movement and manage drivability.

Key Features

• Throttle position sensor for emission control and engine management systems
• Female connector with plug-in connection style
• 4 blade terminals with male terminal design
• Direct-fit style for listed Subaru applications
• Cross-references Beck/Arnley 158-0555 and Four Seasons 75387 for the same application

Detailed Description

Standard Ignition TH389 is built for vehicles that rely on accurate throttle angle feedback to the powertrain control module. This sensor is listed for 1998-2004 Subaru Legacy, 1999-2005 Subaru Impreza, 1999-2004 Subaru Forester, 2000-2004 Subaru Outback, and 2003-2006 Subaru Baja. It also includes a 1999 Subaru Legacy application for vehicles equipped with Federal Emissions. If you are searching for a Subaru Impreza throttle position sensor or a Subaru Forester throttle position sensor, TH389 is a direct part-number match to verify against your vehicle’s original unit.

What It Helps Address

• Throttle response concerns caused by an inaccurate throttle signal
• Check engine light conditions related to throttle position input
• Idle quality issues tied to inconsistent throttle feedback
• Acceleration hesitation from a worn or faulty TPS
• Emission control faults on listed Subaru applications

Installation Notes and Tips

Confirm connector style, terminal layout, and vehicle calibration before installation. This sensor uses a female plug-in connector with 4 blade terminals, so matching the original electrical connection is important. Verify fitment by year, model, and emissions configuration, especially for the 1999 Subaru Legacy Federal Emissions application. For Subaru Legacy, Subaru Outback, and Subaru Baja fitment, compare the original sensor shape and connector orientation before replacement.

Quality Assurance

Standard Ignition is a recognized aftermarket brand for electrical and engine management components. TH389 is cataloged as a throttle position sensor for the listed Subaru fitments and is supported by interchange references for application matching.