B009F: High Voltage Crash Sensor 3

Hardware fault

What B009F means

Sensor 3 rounds out the group of impact sensors the Escalade Hybrid uses to trigger a high voltage disconnect. The module checks each one on every key cycle and compares what comes back to the range stored in its calibration. B009F is the entry it writes when sensor 3 falls outside that range or goes silent.

Owners often read a high voltage code and assume the battery pack is the problem. That is not what this says. The pack can be perfectly healthy while the sensor meant to protect it during a wreck is unreadable, and the restraint module will hold B009F until that input comes back.

Common causes

• A failed sensor 3 that no longer returns a valid signal
• Connector corrosion or a terminal that has spread and lost contact
• Wiring damage in the harness branch feeding sensor 3
• A sensor left loose or shimmed after a repair, so it does not read impact properly
• Water intrusion into the sensor area from a leak or a poorly sealed panel

Crash data or hardware fault?

Hardware codes like B009F describe a part the module is watching in real time, and they clear from the module's perspective once the part reads correctly. Crash data works the other way. After a deployment the module locks a permanent record, and no amount of clearing at the scan tool removes it.

Does our reset clear it?

The mail-in reset erases stored fault memory in the module. That is useful when the sensor has already been replaced or the harness fixed and B009F is simply still listed. It is not a repair for a live sensor fault, and we would rather tell you that up front than take in a module that will set the same code the day it goes back in.

Which makes throw it

Only Cadillac shows B009F in our data, on the Escalade Hybrid platform where the high voltage system carries its own crash detection sensors.

What to do next

Locate sensor 3 on the vehicle and look at its connector and mounting first, since a fastener left loose during a previous repair is quick to find and quick to fix. Test the harness for continuity back to the restraint module before condemning the sensor. When the sensor turns out to be the failed part, we stock genuine OEM sensors and can check availability by VIN at 501-988-0611. Related codes: B0091, B1000, B0085.