DTC U0001
Diagnostic Instructions
DTC Descriptor
DTC U0001 00: High Speed CAN
Communication Bus |
Circuit Description
Modules connected to the GMLAN serial data circuits 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.
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
Reference Information
Schematic Reference
Data Communication Schematics
Connector End View Reference
Component Connector End Views
Description and Operation
Data Link Communications Description and Operation
Electrical Information Reference
Scan Tool References
Control Module References for scan tool information
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