Diagnostic Aids
WARNING: This page is about a different car, the 2002 Chevrolet Monte Carlo, 2002 Chevrolet Impala, 2001 Chevrolet Monte Carlo, and 2001 Chevrolet Impala. However, it is still accessible from the selected car via links, so may be relevant.
BCM detects that ignition is on and send appropriate power mode message to other modules. BCM must be connected to DLC for any other module to communicate with scan tool. When class 2 serial data circuit is shorted to ground, DTC U1300 or U1305 will be set. If DTC U1300 or U1305 is present, go to DTC U1300: CLASS 2 DATA LINK SHORTED TO GROUND . When class 2 serial data circuit is shorted to power, DTC U1301 or U1305 will be set. If DTC U1301 or U1305 is present, go to DTC U1301: CLASS 2 DATA LINK SHORTED TO POWER .