Table A1-4 Data Link Connector (DLC) Diagnosis

Diagnostic Chart:

Wiring Diagram:

Circuit Description

The provision for communicating with the Powertrain Control Module (PCM) is the Data Link Connector (DLC). It is usually located under the instrument panel. The DLC is used to link a scan tool to the PCM serial data stream. Some common uses of the scan tool are listed below:

^ Identifying the stored Diagnostic Trouble Codes (DTCs).

^ Clearing the DTCs.

^ Storing the freeze frame data.

^ Reading the serial data.


Diagnostic Aids

Some scan tools may require an external power supply. Make sure your scan tool is using the correct power read.

Ensure that the correct application (model year, canine, VIN code) has been selected on the scan tool. If communications are still not established, try the scan tool on another vehicle in order to ensure that the scan tool, the Vehicle Interface Module (VIM), or the cables are not the cause of the malfunction.

An intermittent may be caused by a poor connection, a rubbed through wire insulation or a wire broken inside of the insulation.

Any circuitry that is suspect to an intermittent complaint should be thoroughly inspected for the following:

^ Backed out terminals.

^ Improper mating.

^ Broken locks.

^ Improperly formed or damaged terminals.

^ Poor terminal to wiring connections.

^ Physical damage to the wiring harness.

^ Corrosion.


Test Description

The numbers below refer to the step numbers in the Diagnostic Table.

1. The Powertrain OBD System Check prompts the technician to complete some basic checks and store the freeze frame data on the scan tool if applicable. This creates an electronic copy of the data taken when the fault occurred. The information is then stored in the scan tool for later reference.

2. Checks to see if the scan tool can establish communications.

3. Checks for B+ at the DLC.

4. Checks for B+ at the DLC.

5. Checks the ground circuits at the DLC.