B1231: Crash Detected, Event Threshold Exceeded

Stored crash data

What B1231 means

The airbag module is always measuring forces through its crash sensors. It only acts when those forces cross a set threshold high enough to mean a real collision, well above the jolt of a pothole or a curb. B1231 is the code that records that the threshold was exceeded and a crash was detected. In other words, the module saw a genuine crash event and wrote it down.

Once that event is logged, the module locks. A standard scanner that tries to clear B1231 returns an error like cannot execute routine, because this is stored data held in protected memory. The record lives in the module and has to be cleared at the module level.

Common causes

• The vehicle was in a crash that exceeded the deployment threshold
• Crash data is now stored and locked in the control module
• The airbag light stays on and a scanner cannot erase the code
• Often seen with deployed restraints, sometimes after a hard impact even where airbags stayed in

Crash data or hardware fault?

Stored crash data. B1231 is a record of a crash event the module logged. The module hardware is usually healthy and just needs the locked event cleared. That is good news for the owner, because the original module can be restored, keeping its factory VIN coding so it installs ready to go.

Does our reset clear it?

Yes. B1231 is a clean fit for our airbag module reset. We clear the crash event and hard codes and return your module factory-ready, with no VIN reprogramming since it is your own module going back into your own vehicle.

Which makes throw it

B1231 is a Ford-family code, seen on Ford, Lincoln, Mercury, and Mazda. The crash-detected meaning is consistent across them.

What to do next

Confirm any deployed airbags and pretensioners are replaced and the car is properly repaired. A reset clears stored data; the physical repairs are a separate step that comes first. Then mail us the module. We clear B1231 and ship it back ready to install. Related codes: B1193 (crash data locked), B0051 (deployment commanded), and B0010 (passenger frontal).