Important Preliminary Checks Before Starting: Perform
Diagnostic System Check - Vehicle
in Vehicle DTC Information
before using the symptom tables in order to verify that all of the following are true:
| • | The body control module (BCM) can communicate via the serial data link. |
Visual/Physical Inspection
Several of the symptom procedures ask for a careful visual/physical check. This
step is extremely important. It could lead to correcting a problem without further
checks and can save valuable time. These checks include the following:
| • | Inspect the easily accessible or visible system components and harness
connectors for obvious damage or conditions which could cause the symptom. |
Intermittents
Important: Check for proper installation of electrical
components if an intermittent condition exists. Inspect for aftermarket theft deterrent
devices, lights and cellular phones. Ensure that no aftermarket equipment is connected
to the class 2 circuit. If you can not locate an intermittent condition, a cellular
phone signal may cause the condition. Faulty electrical connections or wiring may
also be the cause of intermittent conditions. Refer to
Testing for Intermittent Conditions and Poor Connections
in Wiring Systems.
Poor electrical connections or wiring cause most intermittent conditions. Perform
a careful visual/physical check for the following conditions:
| • | Poor mating of the connector halves or a terminal not fully seated in
the connector body |
| • | An improperly formed or damaged terminal |
| • | Reform or replace connector terminals in the problem circuit in order
to insure proper contact tension. |
| • | Poor terminal to wire connection requires removing the terminal from the
connector body in order to perform the check. |
Use a scan tool in order to help detect intermittent conditions. The scan tool
has several features that can be used to locate an intermittent condition. The snapshot
feature can capture and store data parameters within the scan tool when the malfunction
occurs. This information can then be reviewed in order to see what caused the malfunction.
