Monthly Archives: November 2022

What is an accelerator pedal position sensor (APPS) and is it not simply a throttle position sensor (TPS)? Good questions. The ’94-’98 models equipped with a 12-valve engine and an automatic transmission utilized a TPS. This sensor controlled shift timing and overdrive lockup. The 1998.5-to-present turbo diesels utilize an APPS for engine control and it provides input for automatic transmission (if so equipped). The 2005 to present Turbo Diesels continue to utilize the APPS. However, the sensor has been moved inside the truck and is part of the throttle pedal assembly.

Let’s go back to the easy-to-understand ’94-’98 12-valve engine. The TPS is actually a rheostat or potentiometer, with three electrical terminals [reference voltage, ground (called a return in most Mopar service info) and signal]. The signal has a varying voltage relative to throttle position, less at idle and more at wide open throttle (WOT). Example: at idle 0.6 volts