Circuit Description
The Data Link Connector (DLC) allows the scan tool to interface with the PCM. The DLC provides the power and ground circuits to enable the scan tool. The Class 2 serial data circuit to the DLC allows bi-directional communication between the PCM and the scan tool. If communication between the scan tool and the PCM cannot be established, the procedure in the DLC Diagnosis table should be used to diagnose the condition.
Diagnostic Aids
Check the following items:
| • | For the PCM to establish communication with the scan tool, system voltage must be between 9.0 and 16.0 volts. If system voltage is not within this range, refer to Charging System for diagnosis. |
| • | Ensure that the correct application (model year, carline, 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 a poor connection, rubbed through wire insulation or a wire broken inside the insulation. Check for poor connections or a damaged harness. Inspect the PCM harness and connectors for improper mating, broken locks, improperly formed or damaged terminals, poor terminal to wire connection, and damaged harness. |
Test Description
The numbers below refer to the step numbers on the Diagnostic Table:
Step | Action | Value(s) | Yes | No | ||||
|---|---|---|---|---|---|---|---|---|
1 | Did you perform the Powertrain On-Board Diagnostic (OBD) System Check? | -- | ||||||
2 |
Does the test lamp illuminate? | -- | ||||||
3 | Use a test lamp connected to B+ in order to probe both of the DLC ground circuits (cavities 4 and 5). Does the test lamp illuminate at both CKTs? | -- | ||||||
4 |
Does the test lamp illuminate? | -- | ||||||
5 | Locate and repair the short to voltage in the class 2 serial data circuit. Refer to Wiring Repairs in Wiring Systems. Did you complete the repair? | -- | -- | |||||
6 |
Does the test lamp illuminate? | -- | ||||||
7 |
Was a problem found? | -- | ||||||
8 | Locate and repair the open in the Class 2 serial data circuit. Refer to Wiring Repairs in Wiring Systems. Did you complete the repair? | -- | -- | |||||
9 | Locate and repair the open in the affected DLC ground circuit. Refer to Wiring Repairs in Wiring Systems. Did you complete the repair? | -- | -- | |||||
10 |
Did you complete the repair? | -- | -- | |||||
|
Important:: The replacement PCM must be programmed. Refer to Powertrain Control Module Replacement/Programming . Replace the PCM. Did you complete the repair? | -- | -- |
