B1B83: Seat Weight Sensor 4, Low

Circuit fault

What B1B83 means

Each of the four sensors under the passenger seat reports the load at its own mounting point. Sensor 4 covers the left rear, the inboard corner nearest the console. The occupant classification module watches every input for an electrical value inside a defined band, and B1B83 is written when the left rear signal falls below it.

A low reading at one corner throws off the total the module calculates, which is why the fault matters even though three sensors may be fine. The module needs all four to agree on a believable picture before it decides how the passenger airbag should behave.

Common causes

• A rearward harness section pinched between the seat frame and the floor pan
• Console or center trim work that disturbed the inboard seat wiring
• A sensor at the left rear mount that has failed after repeated loading
• Corrosion in the connector from water that ran down the console area
• A short to ground in the sensor input wire pulling the signal down

Crash data or hardware fault?

B1B83 is a circuit fault, meaning the value is live and changes with the wiring. That makes it fundamentally different from crash data, which is written the moment airbags deploy and stays in module memory permanently. A scan tool clears one of those and not the other.

Does our reset clear it?

Resetting the module will not lift a low input back into range. The occupant classification module measures that circuit continuously, so B1B83 returns as soon as power is restored. Repair the harness or the sensor, then run the calibration the system requires. Our mail-in reset applies to airbag modules carrying crash data or a stored internal hardware fault.

Which makes throw it

In our lookup B1B83 belongs to Chrysler, on passenger seats using the four position weight sensing arrangement.

What to do next

Slide the seat forward and check the inboard rear mounting point first, since the harness there gets trapped when the seat is bolted back down after other work. Inspect the connector for moisture that has tracked down from the console. Test the sensor and the input wire separately so you replace the right one, and finish with the occupant classification calibration. Related codes: B1B7E, B1B88, B1334.