VTD Function Description Explanations

Cranklow: The Cranklow function reads as active when the ignition switch is in the START position. Otherwise, the function will read as inactive.

VTD Option: The VTD Option function indicates whether the instrument cluster has ever detected the presence of a Passlock™ lock cylinder. When the detection occurs, the instrument cluster will set the vehicle theft deterrent (VTD) Option function to YES.

VTD Data: The VTD Data function is an interpreted representation of the VTD Password. The VTD Data function may change 7-10 counts, depending on the operating conditions.

SDL Monitor

Use the scan tool in order to monitor the communications between the following components:

The function is called SDL (serial data link) MONITOR on the scan tool. Refer to the table below for a listing of the Vehicle Theft Deterrent Function Descriptions. The table is broken into display pairs as the scan tool lists 2 function descriptions per screen.

Communication Path	Function Description	Units/Range
Instrument Custer to PCM
	VTD Moding	Set/Not Set
	Reverse Rotate	Active/Inactive
	VTD Password	Receive/Not Receive
	A/C Request	No/Yes
PCM to Instrument Cluster
	Oil Pressure T/T	Off/On
	Reference Sync	Not Sync/Sync
	VTD Acknowledge	No/Yes
	VTD Tamper	Inactive/Active

SDL Monitor Descriptions Explanations

VTD Moding: The VTD Moding Function is SET once the instrument cluster makes a theft decision.

Reverse Rotate: The Reverse Rotate function tells the powertrain control module (PCM) when to make the theft decision. If the Reverse Rotate function status is active, then the instrument cluster determined that the ignition switch is in the START position. Verify that the function reads INACTIVE if the ignition switch is not in the START position. Under certain circumstances, the PCM is able to make a theft decision independent of the Reverse Rotate function.

VTD Password: The VTD Password function indicates whether or not the instrument cluster sent the correct R-Code to the PCM. If the instrument cluster reads an R-Code, the instrument cluster will send the R-Code to the PCM. The VTD Password function will then read as ACTIVE. ACTIVE indicates that the instrument cluster received the R-Code from the Passlock™ lock cylinder. If the instrument cluster did not read an R-Code, the VTD Password function will indicate NOT RECEIVE.

Reference Sync: The Reference Sync function tells the instrument cluster if the engine is cranking.

VTD Acknowledge: The PCM outputs the VTD Acknowledge function if the Pass-Theft condition is present for the ignition cycle.

VTD Tamper: The PCM outputs the VTD tamper function if the PCM determines a Failed-Theft condition for the ignition cycle. The VTD Tamper function may also set if the instrument cluster determines a Failed-Theft condition.