GM Service Manual Online
For 1990-2009 cars only

Object Number: 235791  Size: MF

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 CONTINUOUS MONITORING for the battery voltage report.

Conditions for Setting the DTC

The battery voltage report indicates the battery voltage is below 9.5 volts and CRANK mode is not active.

Action Taken When the DTC Sets

The SDM sets DTC B1327 and disables the State Of Health (SOH) DTCs U1096, U1255, U1300, and U1301.

Conditions for Clearing the MIL/DTC

The SDM receives a battery voltage report message that the battery voltage is above 9.5 volts.

Diagnostic Aids

Refer to Charging System Check in Engine Electrical in order to diagnose a vehicle undercharging condition.

Step

Action

Value(s)

Yes

No

1

Was the SIR Diagnostic System Check performed?

--

Go to Step 2

Go to SIR Diagnostic System Check

2

Install scan tool and check other modules for their input voltage.

Do their input voltage match SDM input voltage?

--

Go to Charging System Check

Go to Step 3

3

Replace the SDM. Refer to Inflatable Restraint Sensing and Diagnostic Module Replacement .

Is the replacement complete?

--

Go to SIR Diagnostic System Check

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