B0015 is GM's code for the deployment loop that runs from the sensing and diagnostic module to the pretensioner built into the driver seat belt retractor. The module measures that circuit constantly and stores B0015 when the reading falls outside its window. The symptom byte that comes with the code is the part that tells you what happened.
The driver belt on a GM vehicle has a pretensioner inside the retractor. In a collision of enough force, the sensing and diagnostic module, the SDM, sends current through the deployment loop to an initiator, the initiator ignites the material in the canister, and the gas that comes off it pulls the slack out of the belt before the occupant loads it. B0015 covers that loop.
GM splits the code by symptom byte, and those two digits do most of the diagnostic work. In GM service data, B0015 01 is a short to battery, 02 is a short to ground, 04 is an open circuit, 0D is resistance above the threshold, and 0E is resistance below it. Write the byte down before anyone clears codes.
The thresholds move by platform. GM data for a 2006 Cadillac STS sets the code above 3.9 ohms or below 1.1 ohms held for 120 milliseconds, while a 2011 platform on the same descriptor uses above 4.2 ohms or below 1.4 ohms held for two seconds. The code runs with ignition voltage between 9 and 16 volts, and the SDM commands the AIR BAG indicator on. History codes clear themselves after a long run of clean ignition cycles, which is how an intermittent disappears before anyone finds it.
B0015 is a circuit report. The SDM is telling you what it measured on a pair of wires, not recording a collision. Repair the circuit and the code stops setting. The overlap is the common one on seat belt work: a belt whose pretensioner fired reads that loop as open, so B0015 with symptom byte 04 often shows up next to stored crash data. The fired belt and the locked module are two repairs, and doing one without the other leaves the light on.
Not on its own. Restoring the module's memory does nothing for a fired pretensioner or a bad connection. If B0015 is the only thing stored, repair the circuit and the light should go out by itself. If the belt deployed, the retractor needs the pretensioner rebuilt through our seat belt pretensioner repair or replaced from our seat belt pretensioner listings, and the module then needs an airbag module reset to clear the deployment record. Do the physical repairs before the reset.
This descriptor belongs to GM's SIR system and turns up on Chevrolet, GMC, Buick, and Cadillac vehicles across the trucks, utilities, and cars that use the newer GM restraint numbering. The same code and symptom bytes carry onto GM built platforms sold under other badges, including the Saab 9-4x, whose service data uses the identical descriptor. Older GM vehicles on the legacy numbering report pretensioner faults under different numbers, so check the code against service data for that year and platform.
Read the code with its symptom byte, then start with the connection under the seat. Run the seat through its full travel while watching the harness, since that is where the stretching happens. Check that the connector is locked and the CPA retainer is present, because a connector that never mated correctly leaves the shorting bar across the circuit and reads low.
A symptom byte of 04 after an accident usually means the pretensioner fired and the belt needs to come out. With no accident history, an open points at the connector or the harness first. B0057 and B0058 cover the passenger pretensioner loop on GM, B0022 is the passenger retractor pretensioner on the newer numbering, and B0016 is the left roof rail loop that often shows up beside it after a side impact.
Related codes: B0022, B0057, B0058, B0016
Keep reading:
Code scope: Chevrolet, GMC, Cadillac, Buick. The same number can mean something different on another manufacturer, so match the code to your make before you act on it.
A reset clears stored crash data. A replacement part fixes a hardware fault. We have read these codes since the nineties and will tell you which one you are looking at.
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