B1B7E: Seat Weight Sensor 2, Low

Circuit fault

What B1B7E means

Weight sensing on this seat works by comparing what each corner carries. The right front sensor takes a share of that load, and the module expects its signal to stay inside a set electrical range whether the seat is empty or occupied. A value below that range sets B1B7E and puts the classification result in doubt.

The right front corner is the one closest to the door, which matters for diagnosis. Its harness runs where feet, cargo, and cleaning water all reach, and that exposure shows up in the kind of faults this position tends to collect. Before ordering a sensor, read all four inputs, since one corner sitting low while the others look normal tells a different story than all four being off.

Common causes

• A connector at the right front sensor that has corroded from floor moisture
• Wiring crushed by cargo or a passenger's heel where it passes the outboard track
• A sensor that has failed internally and no longer returns a valid signal
• Damage from a seat removal where the harness was pulled instead of unclipped
• A short to ground in the seat harness bringing the input line down

Crash data or hardware fault?

The code reads as a circuit fault, meaning it reflects a measurement being taken right now on the sensor input. It clears from the module's view once the reading returns to range. Stored crash data works on different rules. It is written when airbags deploy, stays locked in the module, and cannot be removed with a scan tool.

Does our reset clear it?

A module reset has no effect on a low sensor input, because the fault is out in the seat and the module rechecks it constantly. Fix the wiring or replace the sensor, then run the occupant classification calibration the vehicle calls for. Where our mail-in service belongs is a module holding deployment data or an internal stored fault.

Which makes throw it

Chrysler is the make that carries B1B7E in our data, tied to the right front weight sensor input on the passenger seat.

What to do next

Pull back the carpet edge and trim near the right front seat mount and follow the harness, since damage on this corner usually shows itself before any testing. Unplug the sensor and check its resistance along with the input line back to the module. Replace whichever side fails, then complete the calibration procedure so the system trusts the seat again. Related codes: B1B79, B1B83, B274C-13.