For 1990-2009 cars only
Diagnostic Instructions
| • | Perform the Diagnostic System Check - Vehicle prior to using the diagnostic procedure. |
| • | Review Strategy Based Diagnosis for an overview of the diagnostic approach. |
| • | Diagnostic Procedure Instructions provides an overview of each diagnostic category. |
Diagnostic Fault Information
Circuit | Short to Ground | Open/High Resistance | Short to Voltage | Signal Performance |
|---|---|---|---|---|
Battery Positive Voltage (DLC) | 1 | 1 | -- | -- |
Ground (DLC) | -- | 1 | -- | -- |
1. Scan Tool Does Not Power Up | ||||
Circuit/System Description
The data link connector (DLC) is a standardized 16 cavity connector. Connector design and location is dictated by an industry wide standard, and is required to provide the following:
| • | Scan tool power battery positive voltage at terminal 16 |
| • | Scan tool power ground at terminal 4 |
| • | Common signal ground at terminal 5 |
Diagnostic Aids
| • | 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. |
| • | If the battery positive voltage, ground circuits and connections of the DLC are functioning properly, the malfunction must be due to the scan tool/CANdi module. |
Reference Information
Schematic Reference
Connector End View Reference
Description and Operation
Data Link Communications Description and Operation
Electrical Information Reference
Scan Tool Reference
Control Module References for Scan Tool Information
Circuit/System Testing
- Ignition ON, test for battery voltage between the battery positive voltage circuit of the DLC and ground.
- Test for less than 1 ohm of resistance between the ground circuit of the DLC and ground.
- If all tests normal, refer to the scan tool/CANdi module user guide.
| ⇒ | If less than battery voltage, repair the voltage supply circuit for a short to ground or an open/high resistance. |
| ⇒ | If greater than 1 ohm, repair the ground circuit for an open/high resistance. |
