GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Pontiac 🢒 2001 🢒 Bonneville 🢒 Restraints 🢒 SIR 🢒 DTC B0077

Circuit Description

The inflatable restraint side impact sensor (SIS) - Left loop is a 2 wire circuit. When the ignition is turned ON, the inflatable restraint sensing and diagnostic module (SDM) performs tests to diagnose critical malfunctions within itself. The SDM provides input power to the SIS. When input power is first detected, the SIS responds by performing internal diagnostics. Next the SIS sends an ID message to the SDM. The SDM will consider this to be a valid ID if the response time is less than 5 seconds after the SIS is powered up. The SIS will continually communicate a status message to the SDM. The SDM can reset the SIS by removing and applying power to it.

Conditions for Running the DTC
    • Ignition 1 Voltage is within the normal operating voltage range.
    • Left SIS loop is not shorted to voltage.
    • Left SIS loop is not shorted to ground.

The SDM monitors the inflatable restraint side impact sensor (SIS) loop with the power on.

Conditions for Setting the DTC
    • The SDM has detected one of the following conditions due to a fault in the SIS interface circuit:
       - A valid ID message is not received within 5 seconds of the SIS being powered up.
       - Status message is not received.
    • The SDM has failed twice to reset the SIS.

Action Taken When the DTC Sets

The SDM commands ON the AIR BAG warning lamp via Class 2 serial data.

Conditions for Clearing the DTC
    • The condition responsible for setting the DTC no longer exists and the scan tool Clear DTCs function is used.
    • A history DTC will clear once 255 malfunction free ignition cycles have occurred.

Diagnostic Aids

The following can cause an intermittent condition in the SIS circuit :

    • A short to ground or short to voltage in the SIS circuit
    • High or low resistance in the SIS circuit
    • Inspect the SIS signal and ground circuits carefully for cutting and/or chafing

If any of the above conditions are found refer to Testing for Intermittent Conditions and Poor Connections in Wiring Systems.

Test Description

The number(s) below refer to the step number(s) on the diagnostic table.

  1. Test the Left SIS signal and Left SIS ground circuits for an open or high resistance.

    2.

  2. Test between the Left SIS signal and Left SIS ground circuits for resistance.

    3.

  3. Test the Left SIS signal and Left SIS ground circuits for a short to voltage.

Step

Action

Value(s)

Yes

No

Schematic Reference: SIR Schematics

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 inflatable restraint Side Impact Sensor (SIS) - Left connector. Refer to Inflatable Restraint Side Impact Sensor Replacement .
  3. Inspect both the component and harness sides of the connector for damage or corrosion that may cause a short to ground or a short to voltage. Refer to Testing for Intermittent Conditions and Poor Connections in Wiring Systems.

Does connector exhibits any signs of damage or corrosion?

--

Go to Step 3

Go to Step 4

3
  1. If the component side of the SIS connector is damaged, the SIS must be replaced. Refer to Inflatable Restraint Side Impact Sensor Replacement .
  2. If the harness side of the SIS connector is damaged, replace the harness side of the connector. Refer to Connector Repairs in Wiring Systems.

Did you complete the repair?

--

Go to Step 12

--

4
  1. Reconnect Left SIS connector.
  2. Verify that the connector position assurance (CPA) is properly installed.
  3. Install a scan tool.
  4. Turn ON the ignition, with the engine OFF.
  5. Use the scan tool to request SIR DTCs displayed.

Does the scan tool indicate that DTC B0077 is current?

--

Go to Step 5

Go to Diagnostic Aids

5
  1. Turn OFF the ignition.
  2. Disconnect the inflatable restraint sensing and diagnostic module (SDM) connector. Refer to Inflatable Restraint Sensing and Diagnostic Module Replacement .
  3. Inspect the SDM connector for damage or corrosion that may cause a short to ground or a short to voltage in the Left SIS circuits. 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 10

Go to Step 6

6

  1. Disconnect the Left SIS connector.
  2. Test both Left SIS signal and Left SIS ground circuits for an open or high resistance between the SDM connector and Left SIS connector. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 10

Go to Step 7

7

Test the resistance between the Left SIS signal circuit and the Left SIS ground circuit on the SDM connector. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Does the resistance measure less than the specified value?

OL

Go to Step 10

Go to Step 8

8

  1. Turn ON the ignition, with the engine OFF.
  2. Test both Left SIS signal and Left SIS ground circuits for a short to voltage. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 10

Go to Step 9

9

Replace the Left SIS. Refer to Inflatable Restraint Side Impact Sensor Replacement .

Did you complete the replacement?

--

Go to Step 10

--

10
  1. Reconnect all SIR components.
  2. Use the scan tool in order to Clear the DTCs.
  3. Operate the vehicle within the Conditions for Running the DTC as specified in the text.

Does the DTC reset?

--

Go to Step 11

System OK

11
  1. Turn OFF the ignition.
  2. Replace the SDM. Refer to Inflatable Restraint Sensing and Diagnostic Module Replacement .

Did you complete the replacement?

--

Go to Step 12

--

12
  1. Use the scan tool in order to Clear the DTCs.
  2. Operate the vehicle within the Conditions for Running the DTC as specified in the text.

Does the DTC reset?

--

Go to Step 2

System OK