GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Chevrolet 🢒 2002 🢒 Express 🢒 Restraints 🢒 SIR 🢒 DTC B1001

Circuit Description

When the ignition is turned ON, the inflatable restraint sensing and diagnostic module (SDM) compares the restraints ID stored in the SDM to the restraints ID stored in the powertrain control module (PCM). The restraints ID being compared contains the last four digits of the SDM part number. The SDM then compares the vehicle identification number (VIN) stored in the SDM to the VIN stored in the PCM. For more detailed information concerning the Class 2 data lines, refer to Data Link Communications Description and Operation in Data Link Communications.

Conditions for Setting the DTC

Ignition 1 voltage is within the normal operating voltage range.

Action Taken When the DTC Sets
    • The SDM disables all AIR BAG deployments.
    • The SDM commands ON the AIR BAG indicator.

Conditions for Clearing the DTC
    • The condition responsible for setting the DTC no longer exists.
    • You issue a scan tool CLEAR DTCs command.
    • A history DTC will clear once 255 malfunction free ignition cycles have occurred.

Diagnostic Aids

DTC B1001 is an indication that the restraint ID's stored in both the PCM and SDM do not match or that the VIN's stored in both the PCM and SDM do not match. If the PCM has been replaced, the replacement module needs to be reprogrammed for proper operation.

Test Description

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

  1. This step checks to see if the correct VIN is programmed in the PCM.

    2.

  2. This step explains how to properly program the VIN into the PCM.

Step

Action

Yes

No

Schematic Reference: SIR Schematics

1

Did you perform the Diagnostic System Check - SIR?

Go to Step 2

Go to Diagnostic System Check - SIR

2

  1. Install a scan tool.
  2. Turn ON the ignition, with the engine OFF.
  3. With a scan tool, verify that the PCM is programmed with the correct VIN by comparing the VIN that is stored in the PCM to the VIN plate of the vehicle.

Is the PCM programmed with the correct VIN?

Go to Step 4

Go to Step 3

3

With a scan tool and/or techline machine, program the correct VIN into the PCM. Refer to PCM programming in Engine Controls.

Did you complete the programming procedure?

Go to Step 5

--

4

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

Did you complete the replacement?

Go to Step 5

--

5
  1. Verify that all components, connectors, and CPAs are properly mounted.
  2. Use the scan tool in order to clear the DTCs.
  3. Turn OFF the ignition for 10 seconds.

Are all SIR components properly mounted and connected?

Go to Diagnostic System Check - SIR

--