B1071 is a Mercedes-Benz restraint code and its wording is unusually plain. In the fault list for the restraint systems control unit it reads: there is an external fault in the child seat recognition. The module has checked that system, found a problem, and pointed away from itself and away from the sensor in the passenger seat.
Mercedes calls the passenger seat sensor B48, front passenger seat occupied and child seat recognition. It does two jobs at once. It tells the restraint systems control unit, component N2/7, whether the passenger seat is occupied, and it reads the transponders in a recognized child seat so the passenger airbag can be switched off with a child in that seat.
The codes around B1071 all name B48 directly. B106C is a communication or cable fault at B48, B106D and B106E cover shorts on the component or its signal line, B106F and B1070 report the component as defective, and B1072 says the coding for it is faulty. B1071 is the one in that block that does not blame B48. External means the sensor and its wiring answered correctly and the trouble is on the other side of the conversation, in what the system was asked to recognize.
In practice that puts the child seat, its transponders, and anything sitting between the seat cushion and the sensor at the front of the list.
Neither crash data nor a failed module. B1071 is a live report about a recognition system, and the restraint systems control unit is otherwise doing its job.
What it affects is passenger airbag suppression. The purpose of child seat recognition is that the passenger bag is disabled with a child in the seat and armed for an adult. A fault anywhere in that chain is a fault in the decision itself, which is why the module logs it and turns the lamp on.
No. There is no stored history to erase, so a reset does nothing here and the code sets again. The recognition problem has to be found at the seat.
Our work on Mercedes modules covers the other case entirely. When an N2/7 control unit has locked with crash data from a collision, our airbag module reset clears that record from your original unit so it goes back into the same car. If the sensor in the passenger seat turns out to be the failed part on a B1070 or B106F diagnosis, occupant classification sensors are in the parts store.
This definition comes from the Daimler fault list for the restraint systems control unit and applies to Mercedes-Benz vehicles carrying child seat recognition, which was widely fitted through the W203 era and the models sharing that architecture. The number does not travel. General OBD references list B1071 as an assist airbag module short, and on Chevrolet it is documented as an airbag control module internal fault. A scan tool reading generic body codes can hand you one of those definitions on a Mercedes and send the job in the wrong direction.
Read the module with a tool that addresses N2/7 by its Mercedes description rather than through a generic body code list, because the difference between B1071 and the B48 codes around it is the whole diagnosis.
Then work the seat. Clear everything off the passenger seat, test with the child seat out of the car, and see whether the fault is still present with an empty seat. Check the connector under the seat and confirm the vehicle coding matches the equipment actually fitted. Related codes are B106C for a communication fault at the same sensor, B106F when the sensor itself is defective, and B1022 when the control unit coding is what is wrong.
Related codes: B106C, B106F, B1022
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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