Fig. 1: Identifying Data Link Connector (DLC) Terminals
Courtesy of GENERAL MOTORS CORP.
SCAN TOOL DOES NOT POWER UP
1. Using DVOM connected to ground, backprobe Data Link Connector (DLC) terminal No. 16 (Orange
wire). See Fig. 1
. If battery voltage exists, go to next step. If battery voltage does not exist, repair open or
short to ground in Orange wire between DLC terminal No. 16 and AUX PWR fuse (25-amp) located in
instrument panel fuse block. See appropriate wiring diagram in DATA LINK CONNECTORS article in
WIRING DIAGRAMS.
2. Using DVOM connected to ground, backprobe DLC terminal No. 4 (Black wire). If continuity exists, go
to next step. If continuity does not exist, repair open or short to voltage in Black wire between DLC
terminal No. 4 and ground connection behind left side of instrument panel below instrument panel fuse
block. See appropriate wiring diagram in DATA LINK CONNECTORS article in WIRING
DIAGRAMS.
3. Check for poor connections between scan tool and DLC terminals No. 4 and 16. Repair as necessary. If
DLC connections check okay, go to next step.
4. Scan tool may be malfunctioning. Check scan tool manual for diagnostic procedures. If necessary,
substitute a known-good scan tool.
DIAGNOSTIC TESTS
DTC 12: DIAGNOSTIC SYSTEM CHECK
Description
DTC 12 is always displayed as the first code, indicating diagnostic display is in progress. If DTCs do not
display, go to Testing . If DTCs display, go to appropriate diagnostic procedure. See BCM DTC
DEFINITIONS table under SELF-DIAGNOSTIC SYSTEM.
Testing
1. Turn ignition switch to RUN position. If SECURITY indicator light illuminates, go to next step. If
SECURITY indicator light does not illuminate, go to step 3 .
2. Attempt to enter Body Control Module (BCM) diagnostic mode. If SECURITY indicator light flashes
DTCs, system is operating properly. Go to appropriate diagnostic procedure. See BCM DTC
DEFINITIONS table under SELF-DIAGNOSTIC SYSTEM. If SECURITY indicator light does not
flash DTCs, go to next step.
3. Disconnect Red 2-pin SECURITY indicator light connector. Connect DVOM between ground and Red 2-
pin SECURITY indicator light connector terminal "B" (Dark Green wire). If battery voltage exists with
. If battery voltage does not exist with ignition on, go to next step.
NOTE: If vehicle is equipped with THEFTLOCK(R) anti-theft device, obtain code from
customer prior to disconnecting power to vehicle. See owner's manual for
proper THEFTLOCK(R) procedures.
2000 Cadillac Escalade
2000 ACCESSORIES & EQUIPMENT' 'Body Control Modules - Escalade, Tahoe & Yukon Denali
Microsoft
October-22-10 7:55:08 PM Page 9 ©
2005 Mitchell Repair Information Company, LLC.
