Circuit Description
Modules connected to the GMLAN serial data circuit monitor for serial data communications
on the GMLAN network during normal vehicle operation. Operating information and commands
are exchanged among the modules. Each module on GMLAN network maintains a transmit
error counter (TEC) and a receive error counter (REC). The counter values increase
with detected errors and will decrease with error-free messages. If the TEC value
exceeds 255 the controller removes itself from the network and a DTC U0001
will be set.
DTC Descriptor
This diagnostic procedure supports the following DTC:
DTC U0001 High Speed CAN Communication Bus
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 DTC
| • | 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 DTC
A certain number of no valid transmitted messages on the GMLAN serial data circuits
are detected by the module.
Action Taken When the DTC Sets
| • | The module suspends all message transmission. |
| • | The module uses default values for all parameters received on the GMLAN
serial data circuits. |
| • | The module inhibits the setting of all other GMLAN communication DTCs. |
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. |
Diagnostic Aids
