SRS, SDM, RCM, ACM, ORC. Same computer, a different name on every brand. Here is how to identify the module your vehicle takes, what to check before buying a recycled genuine OEM unit, and when resetting your own beats replacing it.
The airbag control module is the small computer that decides whether your restraint system fires. It is wired to the crash sensors, the airbag inflators, and the seat belt pretensioners, and does nothing until the readings cross the threshold the factory set for a real impact. When they do, it picks which bags go off, whether at full or partial force, and whether the belts cinch a fraction of a second ahead of them.
Every brand calls it something different, which is the first thing that trips people up. Ford and Lincoln say RCM, the restraints control module. Chevrolet, GMC, Buick, and Cadillac say SDM, the sensing and diagnostic module. Chrysler, Dodge, Jeep, and Ram say ORC, the occupant restraint controller. Honda and Acura call it the SRS unit. Toyota and Lexus call it the center airbag sensor assembly. Nissan and Infiniti call it the air bag diagnosis sensor unit. Hyundai and Kia say SRSCM, Mazda says SAS control module, BMW says ACSM. Our explainer on what an SRS airbag module is covers the basics if the term is new to you.
Carmakers mount the module low and near the center of the vehicle, the spot least likely to get crushed: under the center console, on the floor near the transmission tunnel, or under a front seat. Look for a small metal or hard plastic box with one to three keyed multi-pin connectors and two or three mounting bolts.
The number you need is on a label on the case, usually next to a barcode. Toyota and Lexus numbers begin with 89170. Honda and Acura begin with 77960. Nissan and Infiniti use two prefixes, 98820 and K8820, so check both before deciding a number does not exist. Subaru runs 98221 plus five characters. Ford builds its numbers around 14B321, the base number for the restraints control module, and those Ford suffix letters step forward when a design change affects whether parts interchange. GM uses a plain eight-digit number with no family prefix. Photograph the whole label, not just the digits you think matter.
Most airbag lights after a collision are not a dead module. The module did its job, wrote the crash event into protected memory, latched a hard code, and locked itself, and the hardware inside is healthy. Clearing that data with an airbag module reset gives your original part back with its factory coding untouched, which is why it goes back in and works without a scan tool. Pull your code before you shop and check it on our airbag code lookup. Deployment codes such as B0051 point at crash data. Internal-fault codes such as B1000 or B1620 point at the hardware.
Buying a replacement is the right move in a narrower set of cases: a direct hit or a burnt connector, water in the floor pan where it lives, a cracked case, the same internal-fault code returning right after a clean reset, or a module that is gone entirely. That last one comes up more than people expect on theft recoveries and auction cars. Our guide on whether you need a new airbag module walks the decision, and the reset versus replacement comparison puts numbers around both paths.
Whether a replacement works the moment you bolt it in comes down to the brand, and on most modern vehicles a scan tool is involved. Ford runs the RCM through its programmable module installation routine and writes the vehicle's as-built configuration. GM programs the SDM and then runs a separate setup step, because the module stores a primary key and a piece of the VIN and compares both to the body control module at every key-on. When those disagree it sets B1001 and stays down until setup is run on both ends. Chrysler, Dodge, Jeep, and Ram controllers ship locked out and set B2722 until initialized, and they run a configuration check that sets B223B when side airbag content disagrees with the network. Hyundai and Kia use variant coding, and their modules accept only so many coding cycles in a lifetime, worth thinking about on a part that has lived one life already.
Toyota and Lexus come closest to a straight swap, since the factory procedure for the center airbag sensor assembly is bolts, a connector lever, and a system check. Honda and Acura are not, despite the reputation: the factory procedure has you confirm the SRS unit is on current software and initialize the occupant detection system afterward. Volkswagen and Audi are hardest, since component protection has to be released through the factory back end. Mazda sets the sharpest trap of all: the configuration is meant to be read out of the outgoing module before it is unplugged, and once it is gone the only path left is as-built data. Line up a shop with the right tool before the part shows up.
Ford's own guidance on restraint parts states the problem better than anyone. These systems are built for specific vehicles, changes happen even inside a single model year, and a component can physically fit a vehicle it does not belong in. Option content usually splits the numbers. Side curtain airbags, a rollover sensor, and a passenger occupant classification system each change what the module answers for, and it checks that content against the network every time you start the car. Cab and body style split numbers too, so one truck in one model year carrying three or four module numbers is normal.
Supersession is its own hazard. Subaru published a bulletin for 2015 to 2017 Legacy and Outback telling shops that when the newer passenger airbag module goes into an older car, the control module and the airbag assembly have to be replaced together as a matched set. Order against your VIN rather than the model year.
An airbag control module carries no pyrotechnic charge, so it is an ordinary small electronic part and ships the normal way to the lower 48 states with the connector pins protected. Getting it in is mechanically simple: disconnect the battery, let the system power down before you touch a connector, bolt the module in the orientation the old one came out, and plug it back in. What needs a qualified installer is everything after that: verifying the system arms clean and running whatever coding your make requires. Restraint parts are final sale once they ship, with one exception for anything that arrives different from the listing photos, and the terms are on our returns page.
If the donor vehicle had a deployment, yes. The module writes that event into protected memory and latches a hard code, and disconnecting the battery does not erase it. That data has to be cleared in our shop before the module will arm in your vehicle.
On most modern vehicles, yes. Ford writes as-built configuration, GM programs the module and then sets it up against the body control module, Chrysler group controllers need initializing, Honda wants the occupant detection system initialized, and Volkswagen and Audi need component protection released at dealer level. Toyota and Lexus are the closest thing to a straight swap. Plan for the tool before the part arrives.
Only if the part number matches. Restraint electronics change with airbag content, occupant sensing, cab or body configuration, and revisions made inside a single model year. Year and model alone are not enough. Send us your VIN and we will check it against the number on the part in stock.
On a label on the module case, usually next to a barcode. Photograph the entire label including the suffix on the end. On Ford modules the suffix letters change when a design change affects whether parts interchange, so the tail of the number is not decoration.
In most after-crash situations, yes, and you keep your original module with its factory coding already in it, which sidesteps the programming question entirely. Replacement makes sense when the module is physically damaged, water-soaked, or missing. Our reset versus replacement guide covers where the line falls.
Other parts in the catalogue:
Driver airbag: the module in your steering wheel Passenger airbag: the module behind your dashboard Knee airbags: what they do and how to buy the right one Side curtain airbags Seat side airbags Seat belt retractors All part types
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