Mark LT 4WD V8-5.4L VIN 5 (2006)
A1-A3
Normal Operation
The vehicle security module controls the remote keyless entry (RKE) and power door locks. The vehicle security module communicates with the
diagnostic tool through the universal asynchronous receiver transmitter (UART)-based protocol (UBP) communications network circuit 1906 (VT).
Check the UBP circuit between the vehicle security module C3008b and the data link connector (DLC) C251. The total resistance value must not be
more than 5 ohms. If the resistance is more than 5 ohms there is an open in circuit 1906 (VT), damage to the DLC C251, damage to the vehicle
security module C3008b, or a problem in the in-line connector.
Possible Causes
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UBP circuit 1906 (VT) open
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vehicle security module C3008b
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vehicle security module
Test B: The Powertrain Control Module (PCM) Does Not Respond to the Diagnostic Tool
PINPOINT TEST B: THE POWERTRAIN CONTROL MODULE (PCM) DOES NOT RESPOND TO THE DIAGNOSTIC TOOL
