Important Preliminary Checks Before Starting:
- Perform
Diagnostic System Check - Door Systems
before using the symptom tables
in order to verify that all of the following are true:
| • | There are no DTCs set. |
| • | The body control module (BCM) can communicate via the serial data link. |
- Review the system operation in order to familiarize yourself with the
system functions. Refer to the following:
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.
Important: The problem may or may not turn on the SERVICE VEHICLE SOON indicator or store
a DTC. Do not use the symptom tables to diagnose intermittent conditions. The malfunction
must be present in order to locate the problem.
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.
Symptom List
Refer to a symptom diagnostic procedure from the following list in order to
diagnose a symptom that does not set a DTC:
