GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Chevrolet 🢒 2008 🢒 Equinox 🢒 Power and Signal Distribution 🢒 Wiring Systems and Power Management 🢒 DTC B0085 or B0086

Diagnostic Instructions
    • Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure.
    • Review Strategy Based Diagnosis for an overview of the diagnostic approach.
    •  Diagnostic Procedure Instructions provides an overview of each diagnostic category.

DTC Descriptors

DTC B0085 02: LF Side Impact Sensor Short to Ground

DTC B0085 05: LF Side Impact Sensor Short to Battery or Open

DTC B0085 0F: LF Side Impact Sensor Erratic

DTC B0085 39: LF Side Impact Sensor Internal Electronic Failure

DTC B0085 3A: LF Side Impact Sensor Incorrect Component Installed

DTC B0085 71: LF Side Impact Sensor Invalid Serial Data Received

DTC B0086 02: RF Side Impact Sensor Short to Ground

DTC B0086 05: RF Side Impact Sensor Short to Battery or Open

DTC B0086 0F: RF Side Impact Sensor Erratic

DTC B0086 39: RF Side Impact Sensor Internal Electronic Failure

DTC B0086 3A: RF Side Impact Sensor Incorrect Component Installed

DTC B0086 71: RF Side Impact Sensor Invalid Serial Data Received

Diagnostic Fault Information

Circuit

Short to Ground

High Resistance

Open

Short to Voltage

Signal Performance

Left Side Impact Sensor High Circuit

B0085 02

B0085 0F

B0085 05

B0085 05

B0085 0F

Left Side Impact Low Circuit

B0085 02

B0085 0F

B0085 05

B0085 05

B0085 0F

Right Side Impact Sensor High Circuit

B0086 02

B0086 0F

B0086 05

B0086 05

B0086 0F

Right Side Impact Low Circuit

B0086 02

B0086 0F

B0086 05

B0086 05

B0086 0F

Circuit/System Description

The inflatable restraint side impact sensor utilizes a unidirectional 2-wire circuit. The side impact sensor modulates current on the interface to send ID, state of health, and deployment commands to the inflatable restraint sensing and diagnostic module (SDM). The SDM serves as a power source and a ground for the side impact sensor. When the ignition is turned ON and input power from the SDM is first detected, the side impact sensor responds by performing internal diagnostics and sending an ID to the SDM. The SDM considers the ID to be valid if the response time is less than 5 seconds. The side impact sensor continually communicates status messages to the SDM, which determines if a fault is present in the side impact sensor circuit. When a fault is detected, the SDM may reset the side impact sensor up to 2 times by removing and reapplying power to it. If the fault is still present, the SDM will set a DTC.

Conditions for Running the DTC

Ignition voltage is between 9-16 volts.

Conditions for Setting the DTC

All of the following conditions exist for 2.5 seconds:

B0085 02 or B0086 02

    • The side impact sensor has been shorted to ground.
    • The side impact sensor current is greater than 23 mA for longer than 5 milliseconds.

B0085 05 or B0086 05

    • The side impact sensor has been shorted to voltage.
    • The side impact sensor circuit is open.
    • The SDM has not received a message from the side impact sensor for greater than 375 milliseconds.

B0085 0F or B0086 0F

The SDM has received erratic messages from the side impact sensor.

B0085 39 or B0086 39

    • The SDM has received a NOK message from the side impact sensor.
    • The SDM has not received a message.

B0085 3A or B0086 3A

    • The SDM has received an ID message from the side impact sensor, which does not match the ID stored in the SDM memory.
    • The SDM has reset the side impact sensor twice without detecting the correct ID message.

B0085 71 or B0086 71

The SDM has received invalid serial data from the side impact sensor.

Action Taken When the DTC Sets
    • The SDM requests the instrument panel cluster (IPC) to illuminate the AIR BAG indicator.
    • The SIR System is disabled and no deployments are allowed.

Conditions for Clearing the DTC
    • The condition for setting the DTC no longer exists.
    • A history DTC will clear once 100 malfunction-free ignition cycles have occurred.

Reference Information

Schematic Reference

SIR Schematics

Connector End View Reference

Component Connector End Views

Description and Operation

SIR System Description and Operation

Electrical Information Reference

    •  Circuit Testing
    •  Testing for Intermittent Conditions and Poor Connections
    •  Connector Repairs
    •  Wiring Repairs

Scan Tool Reference

Control Module References for scan tool information

Circuit/System Testing

    Important: Refer to SIR Service Precautions.

    When removing connectors, inspect for damage or corrosion. Damage or corrosion in the following requires repair or replacement of the affected component/connector:

       • Side impact sensor
       • SDM module
       • Side impact sensor wiring harness connector
       • SDM wiring harness connector

  1. Ignition OFF, disconnect the appropriate side impact sensor connector.
  2. Disconnect the harness connector at the SDM.
  3. Ignition ON, test for less than 1 volt between the side impact sensor high circuit terminal B and ground.
    4. ⇒If greater than the specified range, test the circuit for a short to voltage.
  4. Ignition ON, test for less than 1 volt between the side impact sensor low circuit terminal A and ground.
    5. ⇒If greater than the specified range, test the circuit for a short to voltage.
  5. Test for infinite resistance between the side impact sensor high circuit terminal B and ground.
    6. ⇒If less than infinite resistance, test the circuit for a short to ground.
  6. Test for less than 1 ohm between the following side impact sensor high circuit terminals.
    7. • Right side impact sensor terminal B and SDM harness connector terminal 43.
    • Left side impact sensor terminal B and SDM harness connector terminal 42.
    ⇒If greater than the specified range, test the circuit for an open/high resistance.
  7. Test for less than 1 ohm between the following side impact sensor low circuit terminals.
    8. • Right side impact sensor terminal A and SDM harness connector terminal 41.
    • Left side impact sensor terminal A and SDM harness connector terminal 40.
    ⇒If greater than the specified range, test the circuit for an open/high resistance.
  8. If all circuits test normal, replace the appropriate side impact sensor.
  9. Reconnect all SIR components. Ignition ON, with a scan tool clear and recheck for DTCs.
    10. ⇒If the side impact sensor DTC returns and is current, replace the SDM.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

    •  Inflatable Restraint Side Impact Sensor Replacement
    •  SIR/SRS Wiring Repairs
    •  Control Module References for SDM replacement, setup, and programming