• | Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure. |
• | Review Strategy Based Diagnosis for an overview of the diagnostic approach. |
• | Diagnostic Procedure Instructions provides an overview of each diagnostic category. |
Circuit | Short to Ground | Open/High Resistance | Short to Voltage |
---|---|---|---|
B+ | U0294 | U0294 | -- |
Ignition+ | U0294 | U0294 | -- |
High Speed GMLAN Serial Data (+) | 1 | U0294 | 1 |
High Speed GMLAN Serial Data (-) | 1 | U0294 | 1 |
Ground | -- | U0294 | -- |
1. Scan Tool Does Not Communicate With High Speed GMLAN Device |
When activated, the data recorded module (DRM) records all of the high speed GMLAN serial data message activity on the bus.
The system voltage is between 9-16 volts.
• | The DTC will set when there is an open/high resistance, short to ground, or short to voltage in the high speed GMLAN serial data circuits. |
• | The DTC will set when there is an open/high resistance or short to ground in the B+ or ignition circuit to the module. |
• | The DTC will set when there is an open/high resistance in the ground circuit to the module. |
The DRM will not record the high speed GMLAN serial data messages.
The current DTC will clear when the malfunction is no longer present.
Data Link Communications Description and Operation
Control Module References for Scan Tool Information
⇒ | If greater than the specified range, test the ground circuit for an open/high resistance. |
⇒ | If the test lamp does not illuminate, test the B+ circuit for a short to ground or an open/high resistance. |
⇒ | If the test lamp does not illuminate, test the ignition voltage circuit for a short to ground or an open/high resistance. |
⇒ | If greater than the specified range, test the serial data circuits for an open/high resistance between the DRM and a module setting the DTC or a serial data splice pack. |
Perform the Diagnostic Repair Verification after completing the repair.
Control Module References for DRM replacement, setup, and programming