Specifications

Chassis Specialist : Electric Power Steering
Page 13
The Koyo system used by the Cobalt, G5, Equinox, Torrent, Ion and Vue is basically the same as the
Delphi system with the exception of the steering wheel position sensor, the PSCM is separate from the
motor and the motor itself is not serviceable. The EPS motor is rated at 58 amps.
The Koyo PSCM contains 8 steering calibrations which are based on the vehicle’s options. The steering
calibrations are based on information stored in the body control module (BCM). Vehicle speed
information to the PSCM is sent via the high speed GM LAN. The PSCM sends a warning message to
the IPC via the GM LAN to indicate a system fault. As with the Delphi system, the Koyo system
protects the EPS motor from thermal damage through software algorithms. Current to the EPS motor
will be reduced by PWM during an overheating situation. As the system does not have a steering wheel
position sensor there will not be any return to centre assist.
Cobalt Steering System