Citizen_GDD

I just got my 2004 S500 detailed and put it in the garage as the temperatures dropped for last 2 days.

I went out to start it up and received a "Key Not Recognized" alert. Car would not start with Keyless Go or with fob in ignition. Tried both keys, same result.

The lights eventually dimmed until dash was completely dark. Car would not lock or unlock. After 10-15 minutes, car would lock & unlock with either key fob, but still will not start.

Any advice or suggestions for troubleshooting? Battery issue?

It was 35 degrees when I had it detailed, but dropped to 15 overnight Saturday and down to 6 by Monday morning. Not sure if this has anything to do with the issue, but providing as background just in case. Car was operating fine immediately after detail.

wallyp

Battery is certainly a good possibility for the cause of the problem. At six degrees, the battery will only put out 35-40% of what it will at 75 deg. If it is a little weak when warm, it will be toast when frigid.

There also are numerous reports of extreme cold causing problems with the EIS, but I would try a warm, fully charged battery first.

Citizen_GDD

Had to go through the whole process of opening the trunk via passenger seat boost.

Volt meter on battery registering at 5.6. Unable to jump start with booster, though did have interior lights for a moment.

Now key will not turn at all in ignition. Calling AAA to see if they can get it jumped so I can take it for a battery replacement.

Citizen_GDD

Called AAA. They came out & installed a new battery, hooking up memory saver prior to install. Everything back in working order.

When I purchased the car, the power trunk was hit-and-miss and the soft close doors were not working. Was told there was an issue with the vacuum motor. With new battery, trunk and soft-close doors working like new. Battery was old. Looked like it may have been original battery (no date sticker).

Thanks for the help.

wallyp

If one of the pneumatic actuators is failing, and takes more time to function than the allowable amount programmed into the PSE (Pneumatic Service Equipment) computer, the computer will stop trying to operate that actuator.

If one of your functions, the trunk soft-close, for example, stops functioning soon, that usually indicates that actuator is leaking or otherwise failing.

To reset the PSE computer, go to the right rear passenger position and find the floor lamp mounted behind the passenger's heel. Pry the lamp housing from the wall and find the yellow 20-Amp fuse near the inner end of the row. Remove it, then put it back in.