GM Service Manual Online
For 1990-2009 cars only

Circuit Description

The supplemental restraint sensing and diagnostic module (SDM) contains a sensing device (accelerometer) that converts vehicle velocity to an electrical signal. The SDM compares this electrical signal to a value stored in memory. When the generated signal exceeds the stored value, the SDM performs additional signal processing and compares the generated signals to values stored in memory. When two of the generated signals exceed the stored values, the SDM will cause current to flow through the inflator modules, deploying the air bags and causing DTC B0051 to set.

This DTC is set when the supplemental restraint sensing and diagnostic module (SDM) has commanded an air bag deployment with no faults present.

Conditions for Running the DTC

SDM must be powered up.

Conditions for Setting the DTC

Ignition voltage must be present and the supplemental restraint sensing and diagnostic module (SDM) must have commanded an air bag deployment.

Action Taken When the DTC Sets

    • The SDM sets a DTC B0051.
    • The SDM commands the AIR BAG warning lamp ON via Class 2 serial data.
    • The SDM records crash data.

Conditions for Clearing the DTC

DTC B0051 is a latched code. You cannot clear a latched code. Replace the SDM after following the instructions in the diagnostic table.

Test Description

The following numbers refer to the step numbers in the diagnostic table:

  1. If the inflator modules has not deployed, DTC B0051 may have set falsely.

  2. If DTC B0051 has set with no signs of impact/collision, the DTC has set falsely.

Step

Action

Value(s)

Yes

No

1

Did you perform the A Diagnostic System Check - SRS?

--

Go to Step 2

Go to Diagnostic System Check - SRS

2

  1. Turn OFF the ignition.
  2. Inspect the vehicle for any signs of air bag deployment.

Does the vehicle show any signs of air bags deployment?

--

Go to Step 5

Go to Step 3

3

Inspect the vehicle and undercarriage for signs of impact/collision.

Does the vehicle show any signs of impact/collision?

--

Go to Step 5

Go to Step 4

4

Replace the supplemental restraint sensing and diagnostic module (SDM). Refer to Supplemental Restraint Sensing and Diagnostic Module Replacement .

Did you complete the replacement?

--

Go to Step 6

--

5

Replace all the components and perform inspections as required following an accident. Refer to Repairs and Inspections Required After a Collision .

Did you complete the appropriate inspections and necessary repairs?

--

Go to Step 6

--

6

  1. Reconnect all SRS components.
  2. Verify that all components, connectors, and CPAs are properly mounted.

Did you complete the action?

--

Go to Diagnostic System Check - SRS

--