U1301

DTC U1300, U1301, OR U1305

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. Symptoms - Vehicle

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

Step 1 - Step 8:

The numbers below refer to the step numbers on the diagnostic table.
3. 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.
5. If there are no current DTCs that begin with a "U", the communication malfunction has been repaired.
6. The communication malfunction may have prevented diagnosis of the customer complaint.