Refer
to Engine Controls Schematic
Power, Ground, MIL, and DLC
, and
Class 2 Data Lines
in Data Link Communications.
Circuit Description
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
| • | If the Class 2 serial data circuit is shorted to ground, U1300 will be set. Refer to DTC U1300 Class 2 Data Link Low . |
| • | If the Class 2 serial data circuit is shorted to battery positive voltage U1301 will be set. Refer to DTC U1301 Class 2 Data Link High . |
Important: Remove any debris from the connector surfaces before servicing a component. Inspect the connector gaskets when diagnosing or replacing a component. Verify that the gaskets are installed correctly. The gaskets prevent contaminate intrusion.
| • | Inspect for the following conditions: |
| - | Faulty terminal connection |
| - | Backed-out terminals |
| - | Improper mating |
| - | Broken locks |
| - | Improperly formed or damaged terminals |
| - | Faulty terminal-to-wire connection--Use a corresponding mating terminal in order to test for proper tension. |
| • | Inspect for a damaged harness. If the harness inspection does not reveal a problem, observe the display on the scan tool while moving connectors and wiring harnesses related to the sensor. A change in the scan tool display may indicate the location of the fault. Refer to Wiring Systems for diagnosis and repair. |
| • | Inspect the PCM and the engine grounds for clean and secure connections. |
If the DTC is determined to be intermittent, reviewing the Failure Records can be useful in determining when the DTC was last set.
Step | Action | Values | Yes | No |
|---|---|---|---|---|
1 | Did you perform the Powertrain On Board Diagnostic (OBD) System Check? | -- | ||
2 |
Does the scan tool communicate with the PCM? | -- | Go to Diagnostic Aids | Go to Scan Tool Does Not Communicate with Class 2 Device in Data Link Communications |
