GM Service Manual Online
For 1990-2009 cars only

Object Number: 397192  Size: MF
SIR Components
SIR System Operation
SIR Handling Caution
Handling ESD Sensitive Parts Notice

Circuit Description

Battery positive voltage (B+) is supplied to the SDM when the ignition switch is in the RUN position via CKT 1139. 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 Setting the DTC

The battery positive voltage (B+) level rises above 15.5 volts for more than approximately 1 second or more.

Action Taken When the DTC Sets

    • Stores a DTC B1328 in the SDM memory.
    • The SDM will not set any communication DTCs.
    • No driver warning message will be displayed for this DTC.

Conditions for Clearing the DTC

The ignition positive voltage level falls below 15 volts for approximately 1 second.

Diagnostic Aids

This DTC may set when the vehicle is placed on a battery charger, on fast charge, for a long period of time.

Test Description

The numbers below refer to the step numbers on the diagnostic table:

  1. Perform the entire SIR Diagnostic System Check before continuing with the diagnosis of this DTC.

  2. Checks that DTC was not set erroneously.

  3. Determines whether the malfunction is in the charging system or the SDM.

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

  1. Turn the ignition switch to the ON position.
  2. Connect a scan tool to the Data Link Connector (DLC).
  3. Select Data from the SDM Data Display. Refer to Scan Tool Data List .

Is Ignition 1 greater than the specified value?

15.5 V

Go to Sensing and Diagnostic Module Integrity Check

Go to Step 3

3

  1. Turn the ignition switch to the ON position.
  2. Disconnect the SDM connector.
  3. Connect a DMM from the SDM harness connector terminal 3 to ground.

Is the voltage greater than the specified value?

15.5 V

Go to Charging System Check in Engine Electrical

Go to Sensing and Diagnostic Module Integrity Check