GM Service Manual Online
For 1990-2009 cars only

Object Number: 381198  Size: MF
SIR Components
SIR Schematics DeVille
SIR Schematics Eldorado
Handling ESD Sensitive Parts Notice
SIR Caution

Circuit Description

The sensing and diagnostic module (SDM) learns the source ID of the battery voltage report message. The SDM monitors this message every 300 milliseconds.

Conditions for Running the DTC

The SDM monitors the class 2 serial data line during the continuous monitoring for the battery voltage report.

Conditions for Setting the DTC

The battery voltage report indicates the battery voltage is above 15.5 volts.

Action Taken When the DTC Sets

The SDM sets DTC B1328 and disables the following State Of Health (SOH) DTCs:

    • DTC U1096
    • DTC U1255
    • DTC U1300
    • DTC U1301

Conditions for Clearing the MIL/DTC

The SDM receives a battery voltage report message that the battery voltage is below 15.5 volts.

Diagnostic Aids

Refer to Charging System Check to diagnose a overcharging condition.