GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Pontiac 🢒 2008 🢒 Vibe - FWD 🢒 Safety and Security 🢒 Supplemental Inflatable Restraints 🢒 DTC B1771

Circuit Description

The seat belt buckle switch circuit - right front consists of a seat belt buckle switch and the passenger presence system (PPS) module. The PPS module monitors the seat belt buckle switch for a buckled/unbuckled state. If the sensing and diagnostic module (SDM) detects a malfunction within the seat belt buckle switch circuit, a DTC will be set.

DTC Descriptor

This diagnostic procedure supports the following DTC:

DTC B1771 Passenger Seat Belt Sensor Circuit

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 - right circuit
    • A short to ground or voltage in the seat belt buckle switch - right circuit
    • A malfunctioning seat belt buckle switch - right
    • A short between the seat belt buckle switch - right circuits
    • An internal PPS module malfunction

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

Test Description

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

  1. Tests the seat belt buckle switch - right circuits for an open or high resistance.

    Tests the seat belt buckle switch - right circuits for a short to ground.

    Tests the seat belt buckle switch - right circuits for a short to voltage.

    2.

  2. Tests to see if the malfunction is caused by the seat belt buckle switch.

Step

Action

Yes

No

Schematic Reference: SIR Schematics

Connector End View Reference: SIR Connector End Views

1

Did you perform the Diagnostic System Check - Vehicle?

Go to Step 2

Go to Diagnostic System Check - Vehicle

2

Is DTC B1771 set as a current DTC?

Go to Step 3

Go to Diagnostic Aids

3
  1. Turn OFF the ignition.
  2. Disconnect the seat belt buckle switch - right front connector.
  3. Inspect both the component and harness sides of the connector for damage or corrosion that may cause the malfunction. Refer to Testing for Intermittent Conditions and Poor Connections .

Does the connector exhibit any signs of damage or corrosion?

Go to Step 4

Go to Step 5

4
  1. If the component side of the seat position sensor connector is damaged, the seat belt buckle - right front must be replaced. Refer to Seat Belt Buckle Replacement - Right Front .
  2. If the harness side of the seat position sensor connector is damaged, replace the harness side of the connector. Refer to Connector Repairs .

Did you complete the replacement?

Go to Step 10

--

5
  1. Turn OFF the ignition.
  2. Disconnect the passenger presence system (PPS) module connector.
  3. Inspect the PPS module connector for the following conditions:
    4. • Corrosion
    • Damaged terminals
    • Poor contact/terminal tension

Did you find and correct the condition?

Go to Step 10

Go to Step 6

6

  1. Test the seat belt buckle - right front circuits for an open or high resistance.
  2. Test the seat belt buckle - right front circuits for a short to ground.
  3. Test the seat belt buckle - right front circuits for a short to voltage.
  4. Test the seat belt buckle - right front circuits for a short between circuits.
  5. All the above conditions refer to Circuit Testing and Wiring Repairs .

Did you find and correct the condition?

Go to Step 10

Go to Step 7

7

Replace the seat belt buckle assembly. Refer to Seat Belt Buckle Replacement - Right Front .

Did you complete the replacement?

Go to Step 8

--

8

  1. Reconnect all SIR components.
  2. Verify that all components, connectors, and connector position assurances (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 9

System OK

9

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

Did you complete the replacement?

Go to Step 10

--

10
  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