The Data Link Connector (DLC) connection is used as an access point for different vehicle diagnostic and programming functions, including those involving the use of a scan tool. Three different types of Serial Data Communications are accessible through the DLC.
Universal Asynchronous Receiver Transmitter (UART)
The UART Serial Data communication relies on a 5 volt digital signal for the exchange of data between different control modules and to provide scan tool diagnostic data. When the ignition switch is in the RUN position and the UART line is at rest, i.e. no communication taking place, the voltage remains HIGH at approximately 5 volts. When data is transmitted the voltage is pulled to ground, approximately 0 volts.
The Supplemental Inflatable Restraint System's Sensing and Diagnostic Module (SDM) utilizes UART communications. The SDM uses UART serial data to allow communication with a scan tool for diagnostic purposes. Diagnostic Trouble Codes (DTC's) stored by the SDM can be retrieved, viewed and cleared with the use a scan tool. A loss of UART communications would prevent the scan tool from communicating with the SDM during SIR system diagnosis.
Class 2
The serial data line is the means by which the microprocessor controlled modules in the vehicle communicate with other control modules and the scan tool.
The control modules on the class 2 data line are as follows:
| • | Electronic Brake Control Module (EBCM) |
| • | Powertrain control module (PCM-Diesel Engines) |
| • | Vehicle control module (VCM-Gas Engines) |
| • | Passlock™ Module |
| • | Vehicle Immobilizer Module (VIM-Export Only) |
Remote Control Door Lock Receiver (Remote Keyless Entry) Programming
The DLC provides a connection to the Remote Control Door Lock Receiver to allow the programming of the receiver to recognize the specific Remote Control Door Lock Transmitters used. If the Remote Control Door Lock Receiver will not respond to programming input, refer to Remote Control Door Lock Receiver Does Not Program in Keyless Entry.
