B1156 says the SRS module found a problem in the front airbag sensor circuit on the right side of the vehicle. Toyota prints it as B1156/B1157/15, one fault carrying two code numbers. The circuit runs from the front of the car back to the module, so the wiring is as much a suspect as the sensor.
Front airbag sensors are the forward crash sensors, mounted up front near the radiator support or the frame horn where they feel a frontal hit before the module does. The right side unit feeds the airbag sensor assembly under the console, and B1156 is stored when the module cannot get a clean signal from it.
The two number format throws people. Toyota lists this fault as B1156/B1157/15, meaning both B1156 and B1157 point at the same right front sensor circuit and share subcode 15. If you searched only one of the two and came up empty, that is why. On the same chart, B1158/B1159/16 is the matching left side fault.
Toyota also notes that this particular code applies to vehicles built without side airbags, running a single stage front system. On a sibling model with side airbags, the same right front sensor fault is filed under a different number, which is worth knowing before you compare notes with someone who has the same year truck.
Circuit. Toyota lists five trouble areas for B1156: the front airbag sensor RH, the airbag sensor assembly, the dash wire, the engine room number 2 wire, and the engine room main wire. Three of those five are harness sections, which tells you where this fault usually hides.
Because the sensor lives at the front of the car, this code often turns up after front end repair work. A sensor that took a hit, a harness that got pulled during a radiator support swap, or a connector never fully latched will all set it.
No. A reset clears stored crash data out of a module. B1156 is the module reporting a live circuit it cannot verify, and it will log again as soon as the key comes on. The sensor or the wiring has to be sorted out first.
Where a reset does belong is the second half of a collision repair. After the front sensors, airbags, and belts are replaced, the module still holds the deployment record from the accident, and our airbag module reset clears that from your original unit. If the sensor is the failed part, genuine OEM front impact sensors are listed by vehicle in the parts store.
This is a Toyota and Lexus code, from the era of charts that pair a B code with a two digit subcode. Later Toyota manuals renumbered the same right front sensor fault to B1610/13, so a 2004 truck and a 2012 truck can have the identical failure under different numbers. Check which chart matches your vehicle before ordering anything.
Read the code with a scanner that reads Toyota body codes, then get to the right front sensor. Inspect the connector for bent or pushed out pins, check the sensor body for cracks or impact marks, and wiggle test the harness along the engine room run with the key on. A resistance check against the left side sensor gives you a fair comparison, since the two are usually the same part number in mirror form.
If the light started after a collision, plan on the sensor and the module both. Related reading here is B1610, which is the same fault under Toyota's later numbering, B1155 for the curtain shield sensor on the left, and B1100 for the module itself.
Related codes: B1610, B1155, B1100
Keep reading:
Code scope: Toyota, Lexus. 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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