GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Chevrolet 🢒 2007 🢒 Optra 🢒 Safety and Security 🢒 Supplemental Inflatable Restraints 🢒 DTC B1401

Circuit Description

When the ignition switch is turned to ON, the sensing and diagnostic module (SDM) will perform a turn-on test to diagnose critical malfunctions within the SDM itself.

These test ignition and deployment loop voltages are measured to ensure that they are within their normal voltage ranges. The SDM monitors the voltages at the driver low and the passenger low to detect shorts to ground or voltage in the deploy loops.

DTC Descriptor

This diagnostic procedure supports the following DTC:

DTC B1401 LF Side Impact Sensor Short to Ground

Conditions for Running the DTC

Ignition voltage is within the normal operating voltage range.

Conditions for Setting the DTC
    • The side impact sensor wiring of the left high is shorted to ground.
    • The side impact sensor wiring of the left low is shorted to ground.

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.

Step

Action

Values

Yes

No

Caution: Refer to Sensing and Diagnostic Module Handling Caution in the Preface section.

Caution: Refer to Sensing and Diagnostic Module Voltage after Ignition is Turned Off Caution in the Preface section.

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
  1. Confirm the ignition switch is OFF.
  2. Wait for 1 minute for the sensing and diagnostic module (SDM) charger to be discharged.

Has the SDM discharged?

--

Go to Step 3

--

3

Visually inspect any damage for the left side impact sensor wiring.

Is the left side impact sensor wiring damaged?

--

Go to Step 5

Go to Step 4

4
  1. Confirm the ignition switch is OFF.
  2. Disconnect the left side impact sensor connector.
  3. Disconnect the SDM connector.
  4. Measure the resistance between the high, low wiring of the left side impact sensor and the ground.

Is the resistance equal to the specified value?

∞

Go to Step 6

Go to Step 5

5

Replace the side impact sensor wiring.

Is the replacement complete?

--

Go to Step 8

--

6
  1. Replace the left side impact sensor. Refer to Inflatable Restraint Side Impact Sensor Replacement.
  2. Confirm the ignition switch is ON.
  3. Use the scan tool in order to clear the DTCs.
  4. Perform the Diagnostic System Check - Vehicle.

Is the DTC removed?

--

Go to Step 8

Go to Step 7

7

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

Is the replacement complete?

--

Go to Step 8

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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 2

System OK