Standard Ignition TH391 Throttle Position Sensor

Throttle Position Sensor for Toyota and Lexus

The Standard Ignition TH391 throttle position sensor provides direct throttle angle feedback for engine management systems on select Toyota and Lexus vehicles. It uses a female connector with a plug-in design, a single 4-blade terminal interface, and OE-style electrical layout for straightforward replacement service.

Key Features

• Throttle Position Sensor for emission control and engine response monitoring
• Female connector, plug-in style
• 1 connector with 4 male blade terminals
• Direct-fit electrical configuration for select Lexus and Toyota applications
• Standard Ignition TH391 replacement part number

Application Details

Standard Ignition TH391 is used to report throttle opening to the vehicle control system, helping the engine computer manage fuel delivery, idle behavior, and acceleration input. It is a practical OE-style replacement for Lexus GS300, GS430, IS300, SC430, ES300, LS430, LX470, and Toyota Camry, Sequoia, and Prius applications listed below. This part cross-references Beck/Arnley 158-0635 for the same application.

Vehicle Fitment

• Fits 2001-2005 Lexus GS300, N/A
• Fits 2001-2005 Lexus GS430, N/A
• Fits 2001-2005 Lexus IS300, N/A
• Fits 2002-2005 Lexus SC430, N/A
• Fits 2002-2004 Toyota Camry, N/A
• Fits 2004 Toyota Sequoia, N/A
• Fits 2002-2003 Lexus ES300, N/A
• Fits 2001-2003 Lexus LS430, N/A
• Fits 2001-2003 Toyota Prius, N/A
• Fits 2001-2002 Lexus LX470, N/A
• Fits 1998-2000 Lexus GS300, N/A, w/o Lever
• Fits 1998-2000 Lexus SC300, N/A, w/o Lever
• Fits 1998-2000 Lexus SC400, N/A, w/o Lever
• Fits 1998 Lexus LX470, N/A, w/o Lever

Common Replacement Symptoms

• Throttle response that feels inconsistent or delayed
• Idle speed fluctuations or unstable idle behavior
• Check engine light related to throttle position input
• Poor acceleration feedback to the engine control module
• Driveability issues tied to throttle signal errors

Installation Notes

Verify connector style, terminal count, and vehicle application before installation. The TH391 uses a female plug-in connector with 4 blade terminals, so matching the original sensor configuration is important for proper electrical connection. Confirm whether the application is listed with or without lever notes before ordering.

Quality Assurance

Standard Ignition supplies replacement sensors built for service on emission control systems and electronic throttle input circuits. The TH391 is cataloged for direct application matching on select Lexus and Toyota models, including 2001-2005 Lexus GS300 and 2002-2004 Toyota Camry coverage.