Circuit Description

WARNING: This page is about a different car, the 2007 Chevrolet Cobalt. However, it is still accessible from the selected car via links, so may be relevant.

The throttle actuator control (TAC) system uses two accelerator pedal position (APP) sensors to monitor the pedal position. Two processors are also used to monitor the TAC system data. The Powertrain control module (PCM) performs an intrusive test in order to detect that the APP signals are not shorted together. The PCM accomplishes this by pulling the APP sensor 2 low momentarily and looking for sensor 1 to also be low. The TAC system also performs this test on the throttle position (TP) sensors. This diagnostic monitors the transistor used to pull one pedal and one throttle sensor to ground simultaneously. Additionally, Both processors monitor each other's data to verify that the indicated APP calculation is correct.

If the transistor does not toggle within a calibrated period, or the indicated APP calculation is incorrect, DTC P1680 sets