GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Pontiac 🢒 2003 🢒 Vibe - FWD 🢒 DTC 🢒 DTC B0127

Circuit Description

The seat belt buckle switch circuit consists of a seat belt buckle switch and the SDM. The SDM monitors the seat belt buckle switch for a buckled/unbuckled state. If the SDM detects a malfunction within the seat belt buckle switch circuit, a DTC will be set.

Conditions for Running the DTC

Ignition 1 Voltage is within the normal operating voltage range.

Conditions for Setting the DTC

The SDM detects a malfunction in the seat belt buckle switch circuit.

Action Taken When the DTC Sets

The SDM commands the AIR BAG indicator ON.

Conditions for Clearing the DTC

The condition responsible for setting the DTC no longer exists and the scan tool Clear DTCs function is used.

Diagnostic Aids

Thoroughly inspect the wiring and the connectors. An incomplete inspection of the wiring and the connectors may result in a misdiagnosis, causing a part replacement with the reappearance of the malfunction.

The following are possible causes of the malfunction:

    • An open or high resistance in the seat belt buckle switch - left circuit
    • A short to ground or voltage in the seat belt buckle switch - left circuit
    • A malfunctioning seat belt buckle switch
    • An internal SDM malfunction

If an intermittent malfunction exists, refer to Testing for Intermittent Conditions and Poor Connections in Wiring Systems.

Test Description

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

  1. Tests the seat belt buckle switch (unbuckled) for the proper resistance value.

    2.

  2. Tests the seat belt buckle switch (buckled) for the proper resistance value.

    3.

  3. Tests for an open, short to ground, or short to voltage in the seat belt buckle switch - left circuit.

Step

Action

Value(s)

Yes

No

SchematicReference: SIR Schematics

Connector End View Reference: SIR Connector End Views

1

Did you perform A Diagnostic System Check - SIR?

--

Go to Step 2

Go to Diagnostic System Check - SIR

2
  1. Turn OFF the ignition.
  2. Disconnect the seat belt buckle switch - left connector.
  3. Inspect both the component and harness sides of the connector for the following conditions:
    4. • Corrosion
    • Damaged terminals
    • Poor contact/terminal tension

Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 9

Go to Step 3

3

Measure the resistance between the seat belt buckle switch terminal and ground with the seat belt unbuckled. Refer to Circuit Testing in Wiring Systems.

Does the resistance measure within the specified range?

1000 -1600 ohms

Go to Step 4

Go to Step 7

4

Measure the resistance between the seat belt buckle switch terminal and ground with the seat belt buckled. Refer to Circuit Testing in Wiring Systems.

Does the resistance measure within the specified range?

100 -500 ohms

Go to Step 5

Go to Step 7

5
  1. Disconnect the SDM connector.
  2. Inspect the SDM connector for the following conditions:
    3. • Corrosion
    • Damaged terminals
    • Poor contact/terminal tension

Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 9

Go to Step 6

6

Test the seat belt buckle swtich circuit for the following conditions:

    • An open or high resistance
    • A short to ground
    • A short to voltage

Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 9

Go to Step 8

7

Replace the seat belt buckle assembly. Refer to Inflatable Restraint Front End Discriminating Sensor Replacement - Left Side .

Did you complete the replacement?

--

Go to Step 9

--

8

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

Did you complete the replacement?

--

Go to Step 9

--

9
  1. Reconnect all SIR components.
  2. Verify that all components, connectors and CPAs are properly mounted.
  3. Use the scan tool in order to Clear the DTCs.
  4. Operate the vehicle within the Conditions for Running the DTC as specified in the supporting text.

Does the DTC reset?

--

Go to Step 2

System OK