Circuit Description
Modules connected to the class 2 serial data circuit monitor
for serial data communications during normal vehicle operation. Operating
information and commands are exchanged among the modules. In addition to
this, Node Alive messages are transmitted by each module on the class 2
serial data circuit approximately once every two seconds. When the module
detects no messages and a high voltage on the class 2 serial data
circuit for approximately 3 seconds, U1301 is set and the setting
of all other class 2 serial communication DTCs is inhibited.
Conditions for Running the DTC
| • | The following diagnostic trouble codes do not have a current status. |
| • | The vehicle power mode requires serial data communication to occur. |
Conditions for Setting the DTC
| • | No valid messages are detected on the class 2 serial data
circuit. |
| • | The voltage level detected on the class 2 serial data circuit
is high. |
| • | The above conditions are met for approximately 3 seconds. |
Action Taken When the DTC Sets
| • | DTC U1301 is stored in the module memory . |
| • | The module uses the default values for any information needed
from the other modules on the class 2 serial data circuit. |
Conditions for Clearing the DTC
| • | A current DTC will clear when a valid class 2 message is
detected on the class 2 serial data circuit or at the end of the current
ignition cycle. |
| • | A history DTC clears after 50 consecutive ignition cycles
without a repeat of the malfunction. |
Diagnostic Aids
