GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Pontiac 🢒 2005 🢒 Vibe - AWD 🢒 Restraints 🢒 SIR 🢒 DTC B1790

Circuit Description

The passenger presence system (PPS) communication circuit consists of the sensing and diagnostic module (SDM) and the PPS module. The SDM monitors the PPS communication circuit. If the SDM detects a malfunction within the PPS communication circuit, a DTC will be set.

DTC Descriptor

This diagnostic procedure supports the following DTC:

DTC B1790 Loss of SIR Communications

Conditions for Running the DTC

Ignition 1 voltage is within the normal operating voltage range.

Conditions for Setting the DTC

The SDM detects a PPS communication circuit malfunction.

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 PPS communication circuit
    • A short to ground or voltage in the PPS communication circuit
    • A short between the PPS communication circuits
    • An internal PPS module malfunction
    • An internal SDM 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. This step tests the PPS communication circuits for an open or high resistance, short to ground or short to voltage.

    2.

  2. This step tests to see if the malfunction is caused by the PPS module.

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 B1790 set as a current DTC?

Go to Step 3

Go to Diagnostic Aids

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

Did you find and correct the condition?

Go to Step 9

Go to Step 4

4
  1. Turn OFF the ignition.
  2. Disconnect the sensing and diagnostic module (SDM) connector.
  3. Inspect the SDM connector for the following conditions:
    4. • Corrosion
    • Damaged terminals
    • Poor contact/terminal tension

Did you find and correct the condition?

Go to Step 9

Go to Step 5

5

Test the PPS communication circuits for the following conditions:

    • An open or high resistance
    • A short to ground
    • A short to voltage
    • A short between circuits
        For all of the above conditions, refer to Circuit Testing and Wiring Repairs .

Did you find and correct the condition?

Go to Step 9

Go to Step 6

6

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

Did you complete the replacement?

Go to Step 7

--

7

  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 8

System OK

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