The data link connector (DLC), which is usually located under the instrument panel, allows a scan tool to communicate with the powertrain control module (PCM). The scan tool is able to perform the following operations when connected to the PCM through the data link connector:
• | Identifying stored diagnostic trouble codes (DTCs) |
• | Clearing DTCs |
• | Performing output control tests |
• | Reading serial data |
Battery power and ground is supplied for the scan tool through the DLC. The Class 2 Serial Data circuit to the DLC allows the PCM to communicate with the scan tool. The Class 2 Serial Data circuit is also used to communicate with the electronic brake control module (EBCM), and the body control module.
Ensure that the correct application (model year, car line, VIN code) has been selected on the scan tool. If communication still cannot be established, try the scan tool on another vehicle to ensure that the scan tool or cables are not the cause of the condition.
An intermittent may be caused by any of the following conditions:
• | A poor connection |
• | Rubbed through wire insulation |
• | A broken wire inside the insulation |
Thoroughly test any circuitry that is suspected of causing the intermittent complaint. Refer to Testing for Intermittent Conditions and Poor Connections in Wiring Systems.
If a repair is necessary, refer to Wiring Repairs or Connector Repairs in Wiring Systems.
The numbers below refer to the step numbers on the diagnostic table:
Step | Action | Values | Yes | No | ||||
---|---|---|---|---|---|---|---|---|
1 | Did you perform the Powertrain On Board Diagnostic (OBD) System Check? | -- | ||||||
2 | With the scan tool, attempt to communicate with the following control modules:
Does the scan tool communicate with these control modules? | -- | Go to Scan Tool Does Not Communicate with Class 2 Device in Data Link Communications | |||||
3 |
Did you find and correct the condition? | -- | ||||||
Important:: The replacement PCM must be programmed.
Did you complete the replacement? | -- | -- | ||||||
5 | With the scan tool, attempt to display PCM Data. Does the scan tool communicate with the PCM? | -- | System OK |