SDL Monitor

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

The function is displayed as serial data link (SDL) 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 Cluster 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 sends the R-Code to the PCM. The VTD Password function then reads as receive. Receive 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.

Troubleshooting Hints

Perform the following procedure before you begin the system diagnosis:

1. If the vehicle does not crank the PASSLOCK™ is not at fault. Refer to Engine Controls.
2. Cycle the ignition switch to RUN, with the engine OFF, in order to inspect the bulb function of the theft deterrent indicator.

If the indicator does not flash after the vehicle stalls, then the PASSLOCK™ System has not been engaged and is not at fault. Refer to Driveability and Emissions in Engine Controls.

3. Visually inspect the following components:

•	The CLS/PCM

•

The PCM

•	The PCM/IGN

•	The CLUSTER fuse

4. If multiple indicators light continuously, inspect for a loss of serial data. Refer to Data Link Connector Schematics
5. Inspect for engine diagnostic trouble codes (DTCs). Refer to Engine Controls.
6. Inspect for instrument cluster DTCs. Refer to Symptom Table in Instrument Panel, Console, and Gauges.

•

Inspect for a broken or partially broken wire inside the insulation. A broken wire can cause system malfunction but prove to be good in a continuity/voltage test with a system disconnected. These circuits may be intermittent or resistive when loaded. Inspect the circuits by monitoring for a voltage drop with the system operational under a load.

•	Inspect for the proper installation of aftermarket electronic equipment which may affect the integrity of other systems. Refer to Cell 4 in Electrical Diagnosis.

System Diagnosis

Perform the Diagnostic System Check. Refer to the Symptom Table for the appropriate diagnostic procedures.