B0016 CHEVROLET – Left Roof Rail Deployment Loop Step 1

Meaning of Code B0016:
This code indicates a problem detected by the Sensing and Diagnostic Module (SDM) in the left roof rail Stage 1 deployment loop. This circuit controls the deployment of the driver’s side side-impact airbag (curtain) during a sufficiently severe side or frontal collision. The SDM continuously monitors the electrical resistance of this loop.

Main Symptom:

• The airbag warning light (SRI – Service Restraint Indicator) remains illuminated on the dashboard.

Possible Causes:

1. Failure of the Left Side Airbag Module (Roof Rail): The module itself may be damaged.

2. Wiring Harness Problem:

   • Open circuit (cut or broken wire).

   • Short to battery (+12V).

   • Short to ground (GND).

   • Excessively high electrical resistance (above the SDM threshold).

   • Excessively low electrical resistance (below the SDM threshold).

3. Faulty Electrical Connection:

   • Improperly seated, loose, or damaged connectors.

   • Broken, bent, pushed back, or corroded connector pins.

   • Oxidation or dirt in the connectors.

4. SDM Module Failure: The airbag control module itself could be the cause (less common).

Diagnostic and Repair Procedure:

1. ABSOLUTE SAFETY: Before any work, disconnect the negative battery terminal and wait for the time specified in the repair manual (usually 10-15 minutes) to allow residual energy to dissipate. Airbags can deploy accidentally, causing serious injury.

2. Visual Inspection:

   • Carefully inspect the wiring harness connecting the SDM to the left side airbag module (roof rail), along its entire length. Look for obvious signs of damage (pinching, chafing, cuts).

   • Thoroughly inspect all involved connectors (at both ends of the harness, at the SDM and at the airbag module). Check:

     • The physical condition of the connector (broken?).

     • The condition of the pins (bent, broken, pushed back, corroded?).

     • The presence of dirt, moisture, or oxidation.

     • Proper connector locking.

3. Electrical Diagnostic (requires specific tools – multimeter, scanner):

   • Using an accurate wiring diagram, check the continuity of the loop circuit.

   • Measure the loop resistance and compare it to the values specified by the manufacturer.

   • Test for the absence of short circuits to ground and to the battery on the relevant wires.

   • Use a scanner capable of communicating with the SDM to read specific sub-codes (B0016-01, -02, -04, -0D, -0E) which specify the type of electrical fault (short to +12V, short to ground, open circuit, high/low resistance). This guides the diagnosis.

4. Repair:

   • If wiring harness/connector problem: Repair or replace the damaged section of the harness. Clean or replace faulty connectors. Ensure perfect connections.

   • If faulty airbag module: Replace the left side airbag module (roof rail). NEVER ATTEMPT TO REPAIR AN AIRBAG.

   • If faulty SDM: Replace the SDM module (after eliminating all other potential causes). Reprogramming is often required.

5. Re-energizing: After repair, reconnect the battery. Clear the fault codes with a scanner. Verify that the SRI light turns off and does not return after a start cycle.

Important Technical Notes:

• Shorting Bars: Airbag module connectors incorporate shorting bars. They automatically connect the “high” and “low” circuits of the deployment loop together when the connector is unplugged. This safety feature prevents accidental deployment during work.

• DTC Sub-Codes: They specify the exact nature of the electrical anomaly detected by the SDM:

  • B0016-01: Short to Battery (+12V)

  • B0016-02: Short to Ground (GND)

  • B0016-04: Open Circuit

  • B0016-0D: Resistance Too High

  • B0016-0E: Resistance Too Low

WARNING: The SIR/SRS (airbag) system is potentially dangerous. If you are not properly trained and equipped, entrust the diagnosis and repair to a certified professional workshop.