The seat position and mirror memory mechanism on my 2002 BMW X5 SUV is really messed up. Most cars with seat and mirror memory have a collection of buttons on the dashboard or door that control the memory. Some cars have an additional feature where you can associate a particular key with a particular setting button. This way, if you open the door with key No. 1, everything will move to the positions associated with button No. 1.

BWM had to do it differently. Its door memory works like you would expect. It also has "key memory," where the settings are remembered in the key itself. When you use the lock button on the key to lock the car, that key remembers the positions that were in effect at that time, and it will restore the seats and mirrors to those positions when you unlock the car using that key.

This design has a number of problems.

Key memory and door memory are independent, which can lead to consumer confusion.

If you lend your car to someone who changes the seat or mirror positions, the key will remember those positions instead of yours when the car is returned (assuming the car was locked using your key).

If you purchase the car with the 16-way "comfort seats" option, there's not enough room in the key to store all 16 positions. Some "less important" positions like lumbar are not saved and restored.

If you set the mirror controls so that the right mirror automatically tilts downward when in reverse (so you can see the curb when parallel parking), and if you don't wait for the mirror to return to its original position before turning off the ignition and locking the car, the position stored in key memory is the current mirror position -- which is going to be somewhere in between the tilted-down and normal driving positions. The car knows perfectly well where the mirror was headed, and it even knows enough to continue raising the mirror if you turn the ignition back on before locking the car. But for some unknown reason, engineers chose to remember this useless mirror position.

I suspect this is why BMW has a configuration option to disable key memory completely. It even asks you to tell the dealer whether you want the key memory enabled in the "How should you configure my car?" pre-delivery questionnaire. Dealers charge money if you later want to change any of these configuration settings (for example, if you want to disable key memory after you figure out the above "features").

This entry was submitted by Steve Glaser and edited by Rob Spiegel.