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 vehicle theft deterrent (VTD) function indicates whether the
instrument cluster has detected the presence of a Passlockā¢ lock cylinder.
When the detection occurs, the instrument cluster sets the 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 powertrain control module (PCM) |
The function is displayed as 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 PCM when to make the theft
decision. If the Reverse Rotate function status is active, then the instrument
cluster has 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 Passlockā¢ 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.