GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Pontiac 🢒 2001 🢒 Grand Am 🢒 Restraints 🢒 SIR 🢒 DTC B0018

Circuit Description

The inflatable restraint IP module deployment loop consists of an inflatable restraint IP module, the IP module - high circuit and IP module - low circuits. A shorting bar is used in the inflatable restraint IP module connector which shorts together the IP module - high and IP module - low circuits when the connector is disconnected. This will help to prevent unwanted deployment of the inflator module during servicing. When the ignition is turned ON, the inflatable restraint sensing and diagnostic module (SDM) performs continuous diagnostic tests on the deployment loops to check for proper circuit continuity and for shorts to ground or voltage. If a malfunction is detected, a diagnostic trouble code (DTC) will be stored.

Conditions for Running the DTC

Ignition 1 Voltage is within the normal operating voltage range.

Conditions for Setting the DTC

The DTC will set if one of the following conditions occurs:

    • The IP module - high input is more than 6 volts for 300 milliseconds.
    • The IP module - high input is less than 2 volts and IP module deployment loop resistance is less than 6 ohms for 300 milliseconds.

Action Taken When the DTC Sets

The SDM commands the AIR BAG Indicator ON 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

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:

    • A short to ground or a short to voltage in the IP module - high or IP module - low circuits.
    • A malfunctioning inflatable restraint IP module.
    • An internal SDM malfunction.

If an intermittent malfunction exists, 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. Tests to see if the malfunction is intermittent.

    2.

  2. Tests to see if the malfunction is caused by the inflatable restraint IP module.

    3.

  3. Tests for a short to ground or voltage in the IP module - high and IP module - low circuits.

Step

Action

Yes

No

Schematic Reference: SIR Schematics

1

Did you perform the Diagnostic System Check - SIR?

Go to Step 2

Go to Diagnostic System Check - SIR

2
  1. Turn OFF the ignition.
  2. Disconnect inflatable restraint IP module connector.
  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 the connector exhibit any signs of damage or corrosion?

Go to Step 3

Go to Step 4

3
  1. If the component side of the IP module connector is damaged, the IP module must be replaced. Refer to Inflatable Restraint Instrument Panel Module Replacement .
  2. If the harness side of the IP module 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 10

--

4

  1. Reconnect the IP module 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. With the scan tool, request the SIR DTC display.

Does the scan tool indicate that DTC B0018 is current?

Go to Step 5

Go to Diagnostic Aids

5

  1. Turn OFF the ignition.
  2. Disconnect the IP module connector.
  3. Connect the J 38715-A SIR Driver/Passenger Load Tool to the wiring harness side of the IP module connector.
  4. Turn ON the ignition, with the engine OFF.
  5. With the scan tool, request the SIR DTC display.

Does the scan tool indicate that DTC B0018 is current?

Go to Step 7

Go to Step 6

6
  1. Turn OFF the ignition.
  2. Replace the inflatable restraint IP module. Refer to Inflatable Restraint Instrument Panel Module Replacement .

Did you complete the replacement?

Go to Step 10

--

7
  1. Turn OFF the ignition.
  2. Remove the J 38715-A .
  3. Disconnect the SDM connector.
  4. Inspect the SDM 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 and Connector Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 10

Go to Step 8

8

Test the IP module - high and IP module - low circuits for a short to ground or 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
  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 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