Speed sensitive power steering

WARNING: This page does not describe the selected car, but rather 7 other vehicles, including the 2007 Volvo V70, 2006 Volvo V70, 2005 Volvo V70, 2004 Volvo V70, and 2003 Volvo V70. However, it is still accessible from the selected car via links, so may be relevant.

Fig 1: Speed Sensitive Power Steering Communication Diagram

Courtesy of VOLVO CARS OF NORTH AMERICA.

The central electronic module (CEM) (4/56) receives information that the engine is running from the engine control module (ECM) (4/46) on the controller area network (CAN). It receives information about vehicle speed from the brake control module (BCM) (4/16). The central electronic module (CEM) then controls the power steering control module which in turn acts on the solenoid.

The central electronic module (CEM) checks the signals. If a fault is detected, the servo assistance is set to normal (approximately 70 km/h) and the system is disengaged. The central electronic module (CEM) also transmits a signal to the driver information module (DIM) (5/1) via the control area network (CAN) which lights the general warning lamp and displays a text message.