Mike's Workshop Manuals: Service manuals for every vehicle
Home >> GMC >> 1987 >> Forward Control 6.2 J, Standard >> Repair and Diagnosis >> External Pages >> Different car >> Section 13 (Engine Controls - Theory & Operation - Gasoline) >> Computerized Engine Controls >> Input Devices >> Digital Ratio Adapter Controller (DRAC)

Digital Ratio Adapter Controller (DRAC)

WARNING: This page does not describe the selected car, but rather 10 other vehicles, including the 1994 GMC Yukon, 1994 GMC Suburban, 1994 GMC Pickup, 1994 GMC Cab & Chassis, and 1994 GMC C3500 HD. However, it is still accessible from the selected car via links, so may be relevant.

DRAC compensates for various axle and tire ratios by monitoring the Vehicle Speed Sensor (VSS) signal and modifying it before passing it on to the PCM and speedometer unit. On models equipped with a DRAC, VSS buffer is an internal part of DRAC.

scientia non olet · About Mike's Workshop Manuals