Scan Tool, PCM Communication Troubleshooting

TROUBLESHOOTING HINTS PCM CLASS-2 DATA LINE
1. Check for proper connection of Scan Tool to Data Link Connector (DLC).
2. Check for loose or missing terminals at DLC.
3. If PCM is not accessible with a Scan Tool, check for an open in PPL (1807) wire between component and DLC terminal 2.
4. Check for proper installation of aftermarket electronic equipment that may affect the integrity of other systems.

Scan Tool Will Not Communicate With Component On UART Data Line (CKT 800):

Scan Tool Will Not Communicate With Component On Class-2 Data Line (CKT-1807):

CIRCUIT OPERATION
A Scan Tool can be connected to the DLC which allows the Scan Tool to communicate with either the PCM or the DERM. System operations can then be monitored for diagnostic purposes.

Data Link Connector (DLC) Pin Assignment:

There are two data lines access with a Scan Tool. Circuit 800 (TAN) UART data line allows the Diagnostic Energy Reserve Module to communicate with the Scan Tool. Circuit 1807 (PPL) CLASS-2 data line allows the Powertrain Control Module to communicate with a Scan Tool.