Circuit Description
The powertrain control module (PCM) on this vehicle uses the class 2 serial data buss strictly for diagnostic purposes. When the PCM detects one of the following conditions on the class 2 serial data circuit for approximately 3 seconds, the setting of all other class 2 serial communication DTCs is inhibited and a DTC will set.
DTC Descriptors
This diagnostic procedure supports the following DTCs:
| • | DTC U1300 Class 2 Data Link Low |
| • | DTC U1301 Class 2 Data Link High |
| • | DTC U1305 Class 2 Data Link Low or High |
This vehicle has DTCs which include DTC Symptoms. For more information on DTC Symptoms, refer to DTC Symptom Description in Vehicle DTC Information.
DTC Symptom | DTC Symptom Descriptor |
|---|---|
00 | No Additional Information |
Conditions for Running the DTCs
| • | Voltage supplied to the module is in the normal operating voltage range. |
| • | The vehicle power mode requires serial data communication to occur. |
Conditions for Setting the DTCs
| • | No valid messages are detected on the class 2 serial data circuit. |
| • | The voltage level detected on the class 2 serial data circuit is in one of the following conditions: |
| - | High |
| - | Low |
| • | The above conditions are met for approximately 3 seconds. |
Action Taken When the DTCs Sets
The module uses default values for all parameters received on the class 2 serial data circuit.
Conditions for Clearing the DTC
| • | A current DTC clears when the malfunction is no longer present. |
| • | A history DTC clears when the module ignition cycle counter reaches the reset threshold, without a repeat of the malfunction. |
Test Description
The numbers below refer to the step numbers on the diagnostic table.
-
If you can communicate with the PCM, the malfunction may be an intermittent short to voltage or ground in the wiring of the class 2 serial data circuit.
-
If there are no current DTCs that begin with a "U", the communication malfunction has been repaired.
-
The communication malfunction may have prevented diagnosis of the customer complaint.
Step | Action | Yes | No |
|---|---|---|---|
Schematic Reference: Data Link Connector Schematics Connector End View Reference: Master Electrical Component List in Wiring Systems | |||
1 | Did you perform the Diagnostic System Check - Vehicle? | Go to Step 2 | Go to Diagnostic System Check - Vehicle in Vehicle DTC Information |
2 |
Can you communicate with the PCM? | Go to Step 4 | |
|
Important:: Turn ON the ignition, with the engine OFF, when testing for a short to voltage. Use the DMM MIN/MAX function to capture intermittent conditions. Test the class 2 serial data circuit for an intermittent short to ground or an intermittent short to voltage. Refer to the following in Wiring Systems: Did you find and correct the condition? | Go to Step 5 | Go to Step 4 | |
4 |
Important: Perform the module setup procedure, if required. Replace the PCM. Refer to Control Module References for the appropriate repair instructions. Did you complete the replacement? | Go to Step 5 | -- |
Did you record any DTCs which begin with a "U" and with a current status? | Go to Diagnostic Trouble Code (DTC) List - Vehicle in Vehicle DTC Information | Go to Step 6 | |
Did you record any DTCs which do not begin with a "U"? | Go to Diagnostic Trouble Code (DTC) List - Vehicle in Vehicle DTC Information | Go to Step 7 | |
7 | Did you diagnose all of the DTCs? | Go to Step 8 | Go to Step 5 |
8 | Use the scan tool in order to clear the DTCs. Did you complete the action? | System OK | -- |
