Electronic Control Module

The Motronic engine management system uses a single Electronic Control Module (ECM) for fuel injection, idle speed control, ignition, and emission controls. See Fig 1 .

The ECM continually corrects air/fuel mixture based on signals from various input devices. The ECM is located underneath center of windshield cowl, behind engine compartment firewall.

Fig 1: Identifying Motronic System Components (VR6 Is Shown; 4-Cylinder Is Similar)

Courtesy of VOLKSWAGEN UNITED STATES, INC.

NOTE: Components are grouped into 2 categories. The first category covers INPUT DEVICES, which control or produce voltage signals monitored by the control unit. The second category covers OUTPUT SIGNALS, which are components controlled by the control unit.