LEMON Manuals: Even more car manuals for everyone
Home >> Buick >> 2008 >> Allure CXL >> Repair and Diagnosis >> External Pages >> Different variant/trim >> Section 9 (Engine Control System & Fuel System - 3.6L - DTC P0335 To DTC P2097) >> DTC P0685, P0686, P0687, P0689, or P0690 >> Circuit/System Description

Circuit/System Description

WARNING: This page is about a different variant/trim than selected.

The Powertrain (PT) relay is a normally open relay. The relay switch is held in the open position by spring tension. Battery positive voltage is supplied directly to the relay coil and the switch contact at all times. The engine control module (ECM) supplies the ground path to the relay coil control circuit via an internal integrated circuit called an output driver.

The ignition 1 voltage that is supplied to the ECM through the ETC fuse, provides power to the internal ECM circuits associated with the throttle actuator control (TAC) operation.