Circuit Description

The ignition 1 voltage circuit supplied by the powertrain relay is used to power the throttle actuator control (TAC) circuitry internal to the engine control module (ECM). The second ignition 1 voltage circuit is supplied by the ignition switch through the ECM 2 fuse, and is used to power the remaining internal ECM circuits. If the ECM detects a voltage difference between the 2 ignition 1 voltage circuits, DTC P1682 will set.