Diagnostic Command Modes: Overview

DIAGNOSTIC COMMAND MODES
The system software includes several self-tests that are performed every time the ignition is turned on and the vehicle is driven. Some of the self-tests occur immediately, while the pump motor active test occurs under normal driving while not in Antilock operation with speeds above 15 MPH. Also, when over 8 MPH the CAB checks continuously for a missing or erratic wheel speed sensor signal.