FixVault

Self-Diagnostic System: Notes

NOTE: DO NOT replace the Body Control Module (BCM) unless a DTC remains current after all DTC repair procedures have been performed. DO NOT replace BCM based on history DTCs.
NOTE: Self-Diagnostic system checks were written specifically for use with Tech II scan tool. Other generic scan tools can be used, but may have limited functions.

Body Control Module (BCM) is equipped with a self-diagnostic system, which detects system DTCs or abnormalities. When a malfunction occurs, BCM will store a DTC. Malfunctions are recorded as history/intermittent failures or as current failures. Current DTCs indicate BCM has detected a fault which is currently present. A history DTC indicates that BCM has previously detected a malfunction that is not currently present.

Begin diagnosis of BCM by performing the diagnostic system check for the system in which the customer concern is apparent. The diagnostic system check will direct you to the correct procedure within the BCM section when a malfunction is present. See DIAGNOSTIC SYSTEM CHECK INDEX  table.

DIAGNOSTIC SYSTEM CHECK INDEX

System Perform Test
Body Control System BODY CONTROL SYSTEM DIAGNOSTIC SYSTEM CHECK 
Air Bag AIR BAG SYSTEM DIAGNOSTIC SYSTEM CHECK 
Anti-Lock Brake ANTI-LOCK BRAKE SYSTEM DIAGNOSTIC SYSTEM CHECK 
Automatic Transmission AUTOMATIC TRANSMISSION POWERTRAIN ON BOARD DIAGNOSTIC SYSTEM CHECK 
Audible Warnings AUDIBLE WARNING DIAGNOSTIC SYSTEMS CHECK 
Body Rear End BODY REAR END DIAGNOSTIC SYSTEM CHECK 
Cruise Control CRUISE CONTROL DIAGNOSTIC SYSTEM CHECK 
Door System DOOR SYSTEMS DIAGNOSTIC SYSTEM CHECK 
Engine Cooling ENGINE COOLING DIAGNOSTIC SYSTEM CHECK 
Engine Electrical ENGINE ELECTRICAL DIAGNOSTIC SYSTEM CHECK 
Horns HORNS DIAGNOSTIC SYSTEM CHECK 
Hydraulic Brakes HYDRAULIC BRAKES DIAGNOSTIC SYSTEMS CHECK 
Instrument Panel Cluster INSTRUMENT PANEL CLUSTER DIAGNOSTIC SYSTEM CHECK 
Lighting Systems LIGHTING SYSTEMS DIAGNOSTIC SYSTEM CHECK 
Manual Transmission MANUAL TRANSMISSION DIAGNOSTIC SYSTEM CHECK 
Powertrain Control Module (2.4L) POWERTRAIN CONTROL MODULE DIAGNOSTIC SYSTEM CHECK (2.4L) 
Powertrain Control Module (3.4L) POWERTRAIN CONTROL MODULE DIAGNOSTIC SYSTEM CHECK (3.4L) 
Radio/Audio System RADIO/AUDIO SYSTEM DIAGNOSTIC SYSTEM CHECK 
Remote Keyless Entry REMOTE KEYLESS ENTRY DIAGNOSTIC SYSTEM CHECK 
Theft Deterrent THEFT DETERRENT DIAGNOSTIC SYSTEM CHECK 
Tire Pressure Monitoring TIRE PRESSURE MONITOR DIAGNOSTIC SYSTEM CHECK 
Variable Effort Steering VARIABLE EFFORT STEERING DIAGNOSTIC SYSTEM CHECK