B1024 is Mercedes-Benz's code for too little resistance in the driver airbag firing circuit. The factory wording is that the ignition circuit with the component R12/13, driver airbag ignition squib 1, is below its allowed resistance. The restraint systems control unit measures that loop at every key on, and a reading under the window means something is bridging the two wires.
R12/13 is the first stage igniter inside the driver airbag. The circuit reaching it leaves N2/7, the restraint systems control unit under the center console, runs up the steering column, and crosses the contact reel to the bag in the wheel. A healthy squib measures a couple of ohms, and B1024 sets when the control unit sees noticeably less than that.
Low resistance means a parallel path. Either the two firing wires are touching each other somewhere, or something is shunting them together at a connector. Every SRS connector on the car has a shorting clip inside it that deliberately bridges the squib pins while the connector is unplugged, which keeps stray voltage from firing the bag with a hand in the way. That clip is supposed to lift as the connector latches home. A connector pushed on but never latched leaves the clip down, and the module reads what looks like a dead short.
B1024 and B1025 are the low and high pair on this one circuit. The same pattern runs through the rest of the Mercedes list, with B1026 and B1027 covering driver squib 2 on a dual stage airbag and B1028 and B1029 covering the front passenger squib. Reading which half is stored saves a lot of probing.
Circuit. N2/7 is telling you what it measured across a pair of wires at key on. Mercedes keeps deployment records under their own numbers, in the 9000 block on the older cars, so B1024 on its own says nothing about whether the vehicle has been hit.
On a collision vehicle expect both kinds of code, and expect to work them in order. Wiring and parts first, then the module's memory.
No. A memory reset restores the control unit to a clean state and clears stored crash data, and it has no effect on two wires touching. The code returns on the next key cycle while the short is still there.
When the contact reel is the failed part, genuine OEM clock springs are searchable by vehicle in the parts store, along with driver airbags. If the airbag deployed and N2/7 locked, our airbag module reset clears the record once the replacement parts are fitted.
B1024 with this definition is Mercedes-Benz, taken from the factory fault list for the N2/7 restraint systems control unit. It covers the C, E, S, CLK, SLK, and ML families and the Sprinter, along with any other model using that controller and its fault set. Other manufacturers use B1024 for their own circuits, so check that the code came from a Mercedes control unit rather than from a code reader guessing at the number.
Start at the connectors, because that is where the shorting clips live. Disconnect the battery, wait out the discharge time, then unplug and firmly relatch the airbag connector and the connector at the base of the contact reel. Listen and feel for the latch. A fair number of these cars arrive after a steering wheel, column, or airbag job where a connector was seated by feel and never clicked home.
If the connectors are right, measure the loop with the airbag disconnected to sort out whether the short is in the harness or in the bag itself. Related codes are B1025 for the same circuit reading high, B1026 and B1027 for the second stage, and B1044 for a coding fault on this circuit. If you need a Mercedes part we do not have listed, send a part request with the model and chassis number.
Related codes: B1025, B1026, B1044
Keep reading:
Code scope: Mercedes-Benz. 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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Mercedes-Benz parts and codes · Do not see it listed? Request a part or call 501-988-0611.