Circuit Description
The Class II 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 16.0V. If system voltage is not within this range, refer to Charging System Check in Engine Electrical 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, Vehicle Interface Module, 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. Refer to Intermittents and Poor Connections Diagnosis and Connector Repairs in Wiring Systems. |
Test Description
The number below refers to the step number on the Diagnostic Table:
Step | Action | Value(s) | Yes | No |
|---|---|---|---|---|
1 | Was the Powertrain OBD System Check performed? | -- | ||
2 |
Does the test lamp illuminate? | -- | ||
3 | Probe the DLC battery feed circuit with a J 35616-200 test lamp to chassis ground. Does the test lamp illuminate? | -- | ||
4 |
Does the voltage measure the specified value? | 0.0V | ||
5 |
Does the voltage measure the specified value? | 0.0V | ||
6 |
Was a problem found? | -- | ||
7 |
Was a problem found? | -- | ||
8 | Locate and repair short to ground in the Class II serial data circuit. Refer to Wiring Repairs . Is the action complete? | -- | -- | |
9 | Locate and repair open in the DLC ground circuit(s) (Terminal 4 or 5). Refer to Wiring Repairs . Is the action complete? | -- | -- | |
10 | Locate and repair open or short to ground in the DLC battery feed circuit. Refer to Wiring Repairs . Is the action complete? | -- | -- | |
|
Important: : The replacement PCM must be programmed. Replace the PCM. Refer to Powertrain Control Module Replacement/Programming . Is the action complete? | -- | -- |
