E 250 V8-5.4L (2008)
Body Control Systems: Initial Inspection and Diagnostic Overview
Inspection and Verification
INSPECTION AND VERIFICATION
1. Verify the customer concern.
2. Visually inspect obvious signs of electrical damage.
VISUAL INSPECTION CHART
Electrical
-
Central junction box (CJB) fuse(s):
-
2 (10A)
-
10 (20A)
-
15 (5A)
-
23 (20A)
-
Wiring, terminals or connectors
-
Vehicle security module (VSM)
3. If an obvious cause of an observed or reported concern is found, correct the cause (if possible) before proceeding to the next step.
4. NOTE: Make sure to use the latest scan tool software release.
If the cause is not visually evident, connect the scan tool to the data link connector (DLC).
5. NOTE: The vehicle communication module (VCM) LED prove-out confirms power and ground from the DLC are provided to the VCM.
If the scan tool does not communicate with the VCM:
-
Check the VCM connection to the vehicle.
-
Check the scan tool connections to the VCM.
-
Refer to Information Bus (Module Communications Network), No Power To The Scan Tool, to diagnose no communication with the scan tool.
6. If the scan tool does not communicate with the vehicle:
-
Verify the ignition key is in the ON position.
-
Verify the scan tool operation with a known good vehicle.
-
Refer to Information Bus (Module Communications Network) to diagnose no response from the PCM.
7. Carry out the network test.
-
If the scan tool responds with no communication for one or more modules, Refer to Information Bus (Module Communications Network).
-
If the network test passes, retrieve and record the continuous memory DTCs.
8. Clear the continuous DTCs and carry out the self-test diagnostics for the VSM.
9. If the DTCs retrieved are related to the concern, go to DTC Charts. For all other DTCs, go to the Diagnostic Trouble Code (DTC) Chart. See:
Diagnostic Trouble Code Descriptions See: Diagnostic Trouble Code Descriptions/Diagnostic Trouble Code (DTC) Chart
10. If no DTCs related to the concern are retrieved, GO to Symptom Chart. See: Symptom Related Diagnostic Procedures
Principles of Operation
PRINCIPLES OF OPERATION
The vehicle security module (VSM) is on the medium speed controller area network (MS-CAN). The VSM controls the power door lock system. The
VSM receives lock/unlock inputs from the door lock control switches. When the VSM receives an lock/unlock command from any door lock control
switch, the VSM activates the door lock actuators. The VSM also controls the remote keyless entry (RKE) transmitter lock/unlock and will activate the
panic alarm (horn sounding and park lights flashing intermittently in regular intervals) when the panic button on the RKE transmitter is pressed. Refer to
Locks.
The VSM receives wireless signal from both the RKE transmitters and the tire pressure monitoring system (TPMS) using the same internal TPMS/RKE
antenna located inside the VSM.
The VSM sends an interior lamp request signal the instrument cluster (IC) when the doors are unlocked using the RKE transmitter. All of the ajar signals
are monitored by the VSM using the CAN to determine if it should send a signal to IC to turn off the interior lamps when the doors locked using the
RKE transmitter. If all of the doors are closed, and the RKE transmitter lock button pressed, the VSM will send a signal to the IC to turn off the interior
lamps. If one or more doors are detected open by the door ajar switches input the VSM, then the VSM will not send a signal the IC to turn off the interior
lamps and they will stay on.
