OBD-II trouble code
B0094: Center Frontal Restraints Sensor (Subfault)
The centre sensor is not a spare for the outer two. Its job is classification — comparing when the middle of the car felt the impact against when the corners did is how the module tells a square head-on from an offset one, and that changes what fires and how hard.
Quick facts
- System
- Body
- Category
- Airbag / SRS Restraints
- Severity
- High severity
- Drivable
- Usually safe to drive short-term
- Repair cost range
- $120 – $1,100
- DIY difficulty
- Shop recommended
What does B0094 mean?
B0094 is stored by the airbag control module against the centre frontal restraints sensor. The circuit is reading outside the tight tolerance restraint circuits are held to, or the sensor has stopped returning data the module considers credible.
The first thing to establish is whether your vehicle has one, because a great many do not. Plenty of designs use only a left and a right forward sensor and leave the middle of the front structure empty. A generic code definition will happily describe a component your car was never built with, and people do spend afternoons removing bumper covers looking for hardware that does not exist. Check the parts diagram for your specific vehicle and build before anything comes apart.
Where it is fitted, its purpose is worth understanding because it is not the obvious one. It is not there as a spare in case one of the outer sensors fails. It is there to let the module classify the crash rather than merely detect it. A collision that strikes the vehicle square in the middle produces a very different sequence to one that catches a corner, and the module reads that difference by comparing the moment the centre of the structure feels the impact against the moment each side does. A square hit reaches the centre and both corners in close succession. An offset or angled hit reaches one corner clearly first, and the centre later and more weakly.
That classification is not academic. It feeds decisions about deployment force on a multi-stage airbag, about whether the seat belt pretensioners fire together or independently, and on some vehicles about how the passenger side is handled given what the occupant classification system is reporting. Losing the centre input removes the module's best means of distinguishing those crash types, and leaves it inferring from two corner readings what it was designed to determine from three.
The causes are shaped by exactly where this sensor lives. A centre frontal sensor is mounted on the middle of the bumper beam, the upper radiator support or the centre of the front structure — which is directly behind the grille and the number plate. That is the busiest square foot on the front of the car for reasons that have nothing to do with crashes. Radiator and condenser replacement, grille removal, front number plate brackets, tow eye covers, parking sensor retrofits, front camera and dashcam installations, bull bars and light bars all involve working in the same space. Fasteners get borrowed, connectors get unclipped for access and forgotten, and harnesses get pinched behind a bumper cover as it is refitted.
Which makes the repair-history question unusually productive here. This code appearing shortly after cooling system work, a grille or bumper removal, or the fitting of any front-mounted accessory is not a coincidence to be dismissed. It is the leading hypothesis, and it is checked with a torch in ten minutes rather than with a meter in an hour.
There is also a low-speed impact route that is specific to the middle of the car. Car park nudges, a kerb-height concrete stop, and reversing contact from another vehicle all land in the centre of the bumper. None of them deploys anything, and none of them leaves damage a driver would think worth mentioning — but all of them can crack a sensor housing, bend a bracket or unseat a connector. If the fault is unexplained, look at the front of the bumper cover for the marks nobody reported.
One parts note worth raising before a price is quoted. On a fair number of vehicles the centre frontal sensor is not a separate part. It is supplied bonded to, or integrated with, the bumper beam or the radiator support assembly, so what looks like a modest sensor replacement becomes a structural component with structural labour behind it. Establish how the part is supplied before committing to a repair, because that single fact can multiply the estimate.
The vehicle drives normally in every respect. This is a restraint system fault, and it should be treated as professional work: the system must be safely disabled with the manufacturer's standing time observed, and a crash sensor that is refitted with the wrong torque or a damaged bracket is a fault the scan tool will not always show.
Common causes
- Connector unclipped for access during radiator, condenser or grille work and not reconnected
- Harness pinched behind the bumper cover during refitting
- Low-speed centre impact from a car park nudge or concrete parking stop
- Cracked sensor housing or bent mounting bracket after minor front-end contact
- Corrosion in the connector from spray drawn straight through the grille opening
- Damage caused by fitting a bull bar, light bar, front camera or parking sensor kit
- Failed centre frontal impact sensor
- Incorrect part fitted, or a sensor from a different build specification
- Shared supply or ground fault affecting several restraints sensors at once
- Failed input channel in the airbag control module
Symptoms
- Airbag or SRS warning lamp illuminated
- B0094 stored in the restraints module
- Vehicle driving entirely normally
- Fault appearing shortly after cooling system, grille or bumper work
- Fault appearing after a front-mounted accessory was fitted
- Unexplained scuffs or a slightly misaligned bumper cover at the centre
- Warning lamp returning after being cleared
- Other frontal restraint codes stored alongside it
Diagnostic steps
- 1.Confirm that your vehicle is actually fitted with a centre frontal sensor before removing anything. Many designs use only left and right forward sensors, and a generic code definition will describe hardware your build does not have. Check the parts diagram for your exact model and specification — this single check saves the most time of anything on this code.
- 2.Ask what has been done to the front of the car recently, and take the answer seriously. This sensor sits behind the grille and number plate, in the same space as radiator and condenser work, grille removal, tow eye covers, parking sensor retrofits, front cameras, dashcams, bull bars and light bars. A connector unclipped for access and forgotten, or a harness pinched as the bumper cover went back on, is the leading cause and is found by looking rather than testing.
- 3.Look at the front of the bumper cover for low-speed impact evidence nobody reported. Car park nudges, concrete parking stops and reversing contact all land in the centre and can crack a housing, bend a bracket or unseat a connector without deploying anything or leaving damage the driver thought worth mentioning.
- 4.Disable the restraint system per the manufacturer's procedure and wait the specified standing time before disconnecting any connector. The system retains enough reserve energy to fire a pyrotechnic device after the battery has been disconnected.
- 5.Read the full restraints fault memory and note the pattern. This code alone points at this sensor and its circuit. This code together with the left and right frontal sensor codes points instead at something they share — a supply, a ground, a common connector or the module — and chasing three sensors separately in that situation wastes the day.
- 6.Inspect the connector and the harness run behind the bumper cover, paying attention to where the loom crosses a beam edge or passes a fastener. Look inside both halves of the connector with a light for corrosion, a backed-out terminal and a seal that has slipped out of its groove.
- 7.Measure the circuit against the manufacturer's specification from both the sensor end and the module end to separate a harness fault from a failed sensor. Restraint circuits use narrow, make-specific bands, so do not work from a generic figure.
- 8.Establish how the part is supplied before quoting a repair. On a number of vehicles the centre sensor comes bonded to or integrated with the bumper beam or radiator support assembly rather than as a separate item, which turns a sensor job into a structural one and changes the price substantially.
- 9.After the repair, clear the code, complete the specified number of ignition cycles and confirm the lamp performs its bulb check and goes out.
Repair cost
$120 – $1,100
Diagnosis is $100 to $200 and needs a scan tool with restraints module coverage. Reconnecting a forgotten connector or repairing a pinched harness is $110 to $320 and is the most frequent outcome given where this sensor lives. A separate centre frontal impact sensor is $70 to $320 for the part with one to two and a half hours of labour, since the bumper cover normally has to come off. The figure to check before committing is whether the sensor is supplied separately at all — on some vehicles it comes integrated with the bumper beam or radiator support, in which case the part alone can be $300 to $700 and the labour rises with it. If several restraint sensors are implicated and the fault traces to the control module, module service or replacement with configuration is $400 to $1,300.
Estimate your repair
Run the numbers for your vehicle
Open the Repair Cost Estimator with airbag / srs crash sensor replacement preselected. Adjust labor rate and vehicle category to fit your situation.
DIY vs shop
Leave this one to a qualified shop. It typically involves emissions-critical components, refrigerant handling, or other work that requires manufacturer-grade tooling, training, or certification. DIY attempts often produce a more expensive problem than the original code.