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 (State of Health) messages are transmitted by each module on the
class 2 serial data circuit about once every two seconds. When the module
detects no messages and a high voltage on the class 2 serial data circuit
for approximately three seconds, U1301 is set and the setting of all
other class 2 serial communication DTCs is inhibited.
Conditions for Running the DTC
| • | Diagnostic trouble code B1327 does not have a current status. |
| • | The vehicle power mode (ignition switch position) 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 three seconds. |
Action Taken When the DTC Sets
| • | DTC U1301 is stored in the memory module. |
| • | The module uses the default values for any information needed
from the other modules on the class 2 serial data line. |
| • | This DTC does not cause a driver warning message to appear. |
Conditions for Clearing the DTC
| • | This DTC clears (status changes from current to history) when
the module detects the class 2 bus is not shorted to battery. |
| • | A history DTC clears after 50 consecutive ignition cycles
if the conditions for setting the DTC are no longer present. |
| • | Current and history DTCs may be cleared manually by using a scan
tool. |
Diagnostic Aids
