GM Service Manual Online
For 1990-2009 cars only
Table 1: DTC B1000 ECU Malfunction

Circuit Description

DTC B1000 is an indication of a potential internal inflatable restraint sensing and diagnostic module (SDM) malfunction. DTC B1000 will set upon detection of any condition in the table below.

Conditions for Setting the DTC

Malfunction

Detection Test

Energy reserve voltage out of normal operating range.

Power-On, continuous monitoring

Microprocessor reserve voltage discharge time failure for three consecutive ignition cycles.

Power-On only

The calculated checksum for internal memory does not match the stored value.

Power-On only

The accelerometer(s) are malfunctioning.

Power-On, continuous monitoring

The driver or passenger current source is malfunctioning.

Power-On, continuous monitoring

The temporary memory storage area is malfunctioning.

Power-On only

The inflatable restraint sensing and diagnostic module (SDM) is unable to read from or write to EEPROM.

Power-On, continuous monitoring

The arming sensor inside the inflatable restraint sensing and diagnostic module (SDM) is not closed during a deployment event.

Power-On only

The device inside the inflatable restraint sensing and diagnostic module that arms the system for deployment is malfunctioning.

Power-On only

The permanent memory storage area is malfunctioning.

Power-On only

Action Taken When the DTC Sets

    • The SDM sets a DTC B1000.
    • The SDM commands ON the AIR BAG warning lamp via Class 2 serial data.

Diagnostic Aids

When you issue a scan tool CLEAR CODES command, some of the indicated malfunctions will only allow the AIR BAG warning lamp to go out briefly and then come back ON.

Test Description

The number(s) below refer to the step number(s) on the diagnostic table.

  1. This step replaces the SDM.

DTC B1000 ECU Malfunction

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

Replace the inflatable restraint sensing and diagnostic module. Refer to Inflatable Restraint Sensing and Diagnostic Module Replacement .

Is the repair complete?

--

Go to SIR Diagnostic System Check

--