Diagnostic Instructions
Circuit/System Description
The data link connector (DLC) is a standardized 16-cavity connector. Design and location is dictated by an industry-wide standard. The following is required to be provided:
| • | Scan tool power battery positive voltage at terminal 16 |
| • | Scan tool power ground at terminal 4 |
| • | Common signal ground at terminal 5 |
The scan tool will power up with the ignition OFF. Some modules, however, will not communicate unless the ignition is ON and the power mode master (PMM) module sends the appropriate power mode message.
Reference Information
Schematic Reference
Data Communication Schematics
Connector End View Reference
Component Connector End Views
Description and Operation
Data Link Communications Description and Operation
Electrical Information Reference
Scan Tool References
Control Module References
for scan tool information
Circuit/System Verification
- Ignition OFF, test for less than 5 ohm between terminal 4 at the data link connector (DLC) and ground.
| ⇒ | If greater than the specified value, test the ground circuit for an open/high resistance. |
- Ignition OFF, test for less than 5 ohm between the DLC terminal 5 and ground.
| ⇒ | If greater than the specified value, test the ground circuit for an open/high resistance. |
- Ignition ON, test for B+ between the DLC terminals 16 and ground.
| ⇒ | If not the specified value, test the B+ circuit for a short to ground or an open/high resistance. |
- If all circuits test normal, refer to the scan tool user guide.
