Bimmerscan

BMW MRS and SRS

One of the most common annoyances associated with the late-model BMWs is the somewhat troublesome air bag warning lamp.

Sometimes the light will stay lit, and then go out after about 3 minutes of driving. Sometimes it will blink and then stay lit. Sometimes it will stay on continuously from when you start the car. Either way, each of these occurrences indicates that the airbag computer (also known as the SRS, or Supplemental Restraint System) has had a problem in the past.

The SRS warning lamp is often triggered for relatively minor reasons that do not require any maintenance on the system. Any number of harmless acts can trigger the SRS lamp:

  • Driving the car through a large puddle, or being exposed to lots of rain
  • Swapping steering wheels
  • Removing the gauge cluster to replace light bulbs
  • Aggressive and/or track driving
  • Accidentally disconnecting an SRS component while hooking up electrical accessories, like an alarm or stereo
  • Pulling a fuse for the SRS system while performing electrical troubleshooting
  • Bad seatbelt sensor in the belt receptacle (common failure)
MRS_Fault

You can’t clear the lamp by disconnecting the battery — it will stay on. Most of the time, the airbag error code will be relatively minor, particularly if you know what caused the error.

In Aug 2008 BMW issued a recall because cracks can develop in the cars’ passenger seat detection mat, deactivating the passenger airbag even when an adult is present.

What is Seat Occupancy Detection

Seat occupancy detection

What is Seat Occupancy Detection II

Seat occupancy detection II