Diagnostic System Check

CAUTION: When disconnecting BCM harness connectors, always disconnect Brown connector first, and reconnect last.

Turn ignition switch to RUN position. If SECURITY indicator light illuminates for 3 seconds, and then turns off, go to step 4. If SECURITY indicator light does not illuminate for 3 seconds, and then turn off, go to next step.
If SECURITY indicator light flashes, go to step 15. If SECURITY indicator light does not flash, go to next step.
Turn ignition switch to START position. If engine starts, go to step 15. If engine does not start, see SYMPTOM TESTS .
Turn ignition switch to START position. If engine starts, go to next step. If engine does not start, go to step 8.
If SECURITY indicator light is on, or customer reports light is on during normal driving conditions, go to next step. If SECURITY indicator light is not on while engine is running, system is okay.
Using scan tool, attempt to communicate with BCM. If communication exists, go to next step. If communication does not exist, go to step 17.
Check for current Passlock™ or engine performance-related DTCs. If any DTCs exist, diagnose and repair as necessary. For engine performance-related DTCs, see appropriate SELF-DIAGNOSTICS article in ENGINE PERFORMANCE. For Passlock™ DTCs, see DIAGNOSTIC TROUBLE CODE INDEX table. If no DTCs exist, diagnose and repair instrument cluster. See appropriate ANALOG INSTRUMENT PANELS article.
If SECURITY indicator light is off, go to next step. If SECURITY indicator light is on, go to step 12.
If engine cranked normally, go to next step. If engine did not crank normally, go to step 11.
Check fuel delivery. See appropriate BASIC DIAGNOSTIC PROCEDURES article in ENGINE PERFORMANCE.
Check starting system. See appropriate STARTERS article in STARTING & CHARGING SYSTEMS.
If SECURITY indicator light is on steady, go to next step. If SECURITY indicator light is not on steady, go to step 15.
Check for current Passlock™ DTCs. If no DTCs exist go to next step. If any DTCs exist, see DIAGNOSTIC TROUBLE CODE INDEX table.
Diagnose and repair instrument cluster. See appropriate ANALOG INSTRUMENT PANELS article.
Check for current Passlock™ or engine-related DTCs. If any DTCs exist, diagnose and repair as necessary. For engine-related DTCs, see appropriate SELF-DIAGNOSTICS article in ENGINE PERFORMANCE. For Passlock™ DTCs, see DIAGNOSTIC TROUBLE CODE INDEX table. If no DTCs exist, diagnose and repair instrument cluster. See appropriate ANALOG INSTRUMENT PANELS article.
Using scan tool, check for current Passlock™ DTCs in BCM. If communication does not exist, go to next step. If any DTCs exist, see DIAGNOSTIC TROUBLE CODE INDEX table.
Repair class 2 serial data line communications. See DATA LINK CONNECTORS article in WIRING DIAGRAMS. After repairs, clear DTCs.