DaimlerChrysler Jeep Grand Cherokee 2002 Service Manual page 24

COMMUNICATION
*PCI BUS COMMUNICATION FAILURE —
TEST
3 Note: Determine which modules this vehicle is equipped with before begin-
ning.
Connect the Diagnostic Junction Port Tester #8339 to the DRB and to the Diagnostic
Junction Port.
Using the DRB, along with the Diagnostic Junction Port Tester #8339, select
Junction Port Tool then PCI Bus Control Mode and follow the instructions on the
DRB.
Note: Perform this function on each pin that is equipped with a PCI Bus
circuit.
Did the DRB display No Modules Responding from any of the pins that were
scanned?
Yes → Go To 4
→ Check the PCI Bus circuit between the DLC and the Diagnostic
No
4 Disconnect the Diagnostic Junction Port Tester cable from the DRB. Keep the tester
connected to the Diagnostic Junction Port.
Turn the ignition on.
Measure the voltage of the PCI Bus circuit on the Diagnostic Junction Port Tester
that the DRB displayed No Modules Responding.
Is the voltage steadily above 7.0 volts?
Yes → Go To 5
→ Go To 6
No
5 Measure the voltage of the PCI Bus circuit on the Diagnostic Junction Port tester
that previously measured above 7.0 volts.
Note: Turn the ignition off before disconnecting any module harness
connector then turn the ignition on.
Disconnect the module harness connector(s).
NOTE: If the problem occurred on a bus circuit that has more than one
module on the same circuit, observe the voltmeter while disconnecting each
module connector one at a time.
Is the voltage steadily above 7.0 volts with the module(s) disconnected?
Yes → Repair the PCI Bus circuit that measured over 7.0 volts for a
→ Replace the module that when disconnected the short to voltage
No
6 Disconnect the Diagnostic Junction Port Tester cable from the DRB. Keep the tester
connected to the Diagnostic Junction Port.
Turn the ignition off.
Disconnect the negative battery cable.
Measure the resistance between ground and the PCI Bus circuit on the Diagnostic
Junction Port Tester that the DRB displayed No Modules Responding.
Is the resistance below 100.0 ohms?
Yes → Go To 7
→ Go To 8
No
ACTION
Junction Port connector for a short to voltage or to ground, repair
as necessary.
Perform BODY VERIFICATION TEST - VER 1.
short to voltage.
Perform BODY VERIFICATION TEST - VER 1.
was eliminated.
Perform BODY VERIFICATION TEST - VER 1.
Continued
16
APPLICABILITY
All
All
All
All