Test B: No Communication On Class-2 Serial Data Link

NOTE: If scan tool does not turn on, perform TEST A: SCAN TOOL DOES NOT POWER UP before proceeding.

Turn ignition off. Access BCM. See COMPONENT LOCATIONS . Disconnect Pink 24-pin BCM connector J3. Using a DVOM, check for open, short to ground or short to voltage in Purple wire between BCM connector terminal B9 and DLC terminal No. 2. See Figure and Figure . See DATA LINK CONNECTORS article in WIRING DIAGRAMS. Repair as necessary and retest operation. If Purple wire checks okay, go to next step.
Turn ignition off. Reconnect BCM. Disconnect one class-2 module at a time. See COMPONENT LOCATIONS . DO NOT disconnect BCM. Turn ignition on. Using scan tool, attempt to establish communications with BCM. If scan tool is able to communicate with BCM, fault is in class-2 module that was disconnected. Replace faulty module. If scan tool is still unable to communicate with BCM, go to next step.
Turn ignition off. Reconnect all previously disconnected class-2 modules. Disconnect Pink 24-pin BCM connector J3. Turn ignition on. Using a DVOM, measure voltage on Purple wires between ground and BCM harness connector J3 terminals A10, B9 and B10. If voltage is less than .1 volt and does not fluctuate on any circuit, check for short to ground in affected circuit. Repair as necessary and retest. If voltage is .1 volt or more, go to next step.
If voltage is constantly more than 4 volts on any circuit, check appropriate Purple wire for short to voltage. Repair as necessary and retest operation. If voltage is 4 volts or less on all circuits, replace BCM. See BODY CONTROL MODULE under REMOVAL & INSTALLATION.