Some 2007-09 Mazda CX-9 SUVs may illuminate the air bag warning light on the dash and log trouble code B2290 (seat weight sensor signal malfunction) in computer memory.
According to Mazda, the condition only afflicts vehicles built prior to April 23, 2008, and most likely is due to excessive static electricity on the passenger seat cover interfering with the signal between the seat weight sensor and the SAS control module.
Installing an updated control module that can filter out the interference, part No. TD11-57-K30D, should put an end to the problem.
"Factory Fixes" is written by Jim DePalma, a 30-year veteran of the auto repair business who has served stints as a service manager, parts manager and ASE-certified technician. His column provides vehicle manufacturers' authentic factory technical service bulletins (TSBs) that have been condensed for easier reading. Mr. DePalma advises that techs always check with a dealer or repair information system for the latest revisions before starting to work on a vehicle. He can be reached via email at [email protected].