GM Service Manual Online
For 1990-2009 cars only

Circuit Description

The inflatable restraint Diagnostic Energy Reserve Module (DERM) detects a closure of the inflatable restraint arming sensor when the voltage at the Driver Side High terminal B9 measures within the amount of its deployment loop supply voltage. The DERM detects a closure of either inflatable restraint discriminating sensor when the voltage at the Driver Side Low terminal B8 measures within the specified amount of ground potential. When both conditions are met simultaneously for no less than 250 microsecond, the DERM records Crash Data and sets the DTC B1051.

Conditions for Setting the DTC

The DTC sets when the DERM detects simultaneously the closure of the inflatable restraint arming sensor and at least one inflatable restraint discriminating sensor for no less than 250 mircoseconds.

Action Taken When the DTC Sets

The DERM turns on the AIR BAG warning lamp, records the Crash Data, and sets a diagnostic trouble code.

Conditions for Clearing the DTC

The DTC clears when the DERM receives a scan tool Clear Codes command.

Test Description

Refer to step numbers on the diagnostic table.

  1. Start at the SIR Diagnostic System Check for all diagnosis.

  2. When DTC B1042 and DTC B1051 are set simultaneously, perform the DTC B1042 diagnosis first.

  3. If the inflatable restraint steering wheel inflator module has not deployed, DTC B1051 may have set falsely.

  4. If DTC B1051 has set with no signs of frontal impact, the diagnostic trouble code DTC has set falsely.

  5. When a frontal crash has occurred, it is necessary to perform the indicated procedures to ensure the SIR system is fully functional.

  6. This test checks for a DERM malfunction setting the DTC.

  7. This test checks for a DERM malfunction setting the DTC.

  8. This test determines whether the DTC was set inadvertently during diagnosis or by a DERM malfunction.

When measurements are requested in this table, use J 39200 Digital Multimeter with correct terminal adapter from J 35616 Connector Test Adapter Kit. When a check for proper connection is requested, refer to Intermittents and Poor Connections in Section 8A4. When a wire, connector or terminal repair is requested, use J-38125 Terminal Repair Kit and refer to Wiring Repair.

DTC B1051- Frontal Crash Detected

Step

Action

Value

Yes

No

1

Was the SIR Diagnostic System Check performed?

Go to Step 2

SIR Diagnostic System Check

2

Using the scan tool, request the SIR Diagnostic Trouble Code display.

Is the DTC B1042 current?

DTC B1042 Loop Energy Reserve Voltage Low

Go to Step 3

3

Turn OFF the ignition switch.

Has the inflatable restraint steering wheel inflator module deployed?

Go to Step 5

Go to Step 4

4

  1. Inspect the front of the vehicle.
  2. Inspect the undercarriage for signs of impact.

Are there signs of impact?

Go to Step 5

Go to Step 6

5

Replace the components and perform inspections. Refer to Repairs and Inspections Required After a Collision

Have the accident repairs been completed?

Go to Step 9

6

  1. Turn ON the ignition switch.
  2. Using the Scan Tool SIR Data List Function select Deploy Command.

Is the deploy command active?

Integrity Check

Go to Step 7

7

Clear the SIR Diagnostic Trouble Codes.

Is DTC B1051 set?

Integrity Check

Go to Step 8

8

Turn OFF the ignition switch.

Was DTC B1051 set when the SIR Diagnostic System Check was first performed?

Integrity Check

SIR Diagnostic System Check

9

  1. Reconnect all the SIR system components.
  2. Ensure that the components are properly mounted.

Have all the SIR system components been reconnected and mounted?

Go to Step 10

10

Clear the SIR Diagnostic Trouble Codes.

Have the SIR Diagnostic Trouble Codes been cleared?

SIR Diagnostic System Check