Diagnostic Aids
WARNING: This page is about a different car, the 2002 GMC Savana Special, 2002 GMC Savana Camper Special, 2002 GMC Savana, and 2002 Chevrolet Chevy Express. However, it is still accessible from the selected car via links, so may be relevant.
System voltage must remain between 9-16 volts for serial data communication.
Always store control module - Alternative Fuels ECM, PCM DTC information into a scan tool before proceeding with diagnosis. The stored control module DTC information may contain Freeze Frame data or Failure Records useful for intermittent diagnosis. Clearing DTC information with a scan tool or the loss of control module power or ground will erase the control module DTC information. Some diagnostic procedures call for disconnection of control module connectors and loss of control module stored DTC information may occur.