Dodge Ram 2004, Service Manual

Page: 288 / 642

Symptom:
*NO RESPONSE FROM FRONT CONTROL MODULE
POSSIBLE CAUSES
ATTEMPT TO COMMUNICATE WITH ANOTHER MODULE
OPEN GROUND CIRCUIT(S)
OPEN FUSED IGNITION SWITCH OUTPUT CIRCUIT
OPEN PCI BUS CIRCUIT
FRONT CONTROL MODULE
TEST ACTION APPLICABILITY
1 Turn the ignition on.
With the DRB, attempt to communicate with the Airbag Control Module.
With the DRB, attempt to communicate with the Controller Antilock Brake (CAB)
module.
With the DRB, attempt to communicate with the Instrument Cluster.
Was the DRB able to I/D or communicate with any of the modules? All
Yes
→
Go To 2
No
→
Refer to symptom list for problems related to the PCI Bus
Communication Failure.
Perform BODY VERIFICATION TEST - VER 1.
2 Turn the ignition off.
Remove the Front Control Module from the IPM.
Using a 12-volt test light connected to 12-volts, probe each Ground circuit in the IPM
FCM connector.
Is the test light illuminated for each circuit? All
Yes
→
Go To 3
No
→
Repair the Ground circuit(s) for an open between the IPM
connector and the grounding point. If OK, replace the power
distribution center.
Perform BODY VERIFICATION TEST - VER 1.
3 NOTE: Check IPM fuse #50 for an open before continuing.
Turn the ignition off.
Remove the Front Control Module from the IPM.
Turn the ignition on.
Using a 12-volt test light connected to ground, probe the Fused Ignition Switch
Output circuit in the IPM FCM connector.
Is the test light illuminated? All
Yes
→
Go To 4
No
→
Check IPM fuse #50 for an open. If OK, replace the power
distribution center.
Perform BODY VERIFICATION TEST - VER 1.
274
COMMUNICATION