My car starts fine; however, if while running (e.g., in Park) any door opens and closes the Key Not Detected dash light comes on. It will go off If I turn the car off and restart it. The FOB has a new battery; actually, this problem occurs no matter which of the 2 original FOB's I use. Baffled!
If possibly related, I changed the car battery recently.

 

Strange, but with the only clue of recently replaced battery the following may help. Read the caution below before proceeding.

Turn off the vehicle and remove the keys from the vehicle .. take them out of range if possible.
Wait 5 or 10 mins and disconnect the battery. [min 2 mins]. Negative ground terminal disconnect should be done. [Safety reasons].
Let the vehicle stay unconnected to the battery for about 20 mins.
Reconnect the battery with a single decisive action. Don't panic as some sparks may be visible. Half decisive action causes multiple connects and disconnects that cause problems.
Tighten the clamp. check the other terminal too. Don't go ape, but make sure the terminal can not be twisted.

Caution: You may loose some settings such as seat preset , radio presets, window/hatch pinch protection.

Salim

ps: Just make sure the key-fob batteries are fresh or replaced per service manual service items.

 

Thanks, this really worked. Then I let the car sit a few weeks in cold winter weather (my wife bought a new Lexus). The 2010 has the new battery in it (car and fob). But when I went to start it, it sounded like the starter turned but didn't seem like the engine did; when I released the Start button it kept whirling maybe 30 seconds. I turned everything off and tried again; after 10 seconds it started up, a bit rough at first then just fine. However, when I drove, to pick up my grandson at school, when he opened and closed the back passenger door the old "Key not Detected" light came on. Back home I went through the same process you suggested earlier, and it works, everywhere except the rear door (he slams). Maybe I read somewhere there is some sort of sensor (switch) in the door, maybe the rear specifically that may cause this problem. Any insights or suggestions? Thanks again, Greg!

 

From how you described the problem, it seems the starter motor is acting up and it might need servicing or replacement. You can go to auto-electric/starter service to have it looked at and make a diagnosis. Electronics and electromechanical stuff do not like cold. Solenoid [appendage on the starter] is responsible for engaging the gear from starter to the flywheel on the engine. These days no one dives down into repairing the problem part and they change the full assembly [read starter]. That may be the cheapest solution as in the other case you have to pay for the failing part but lot more for the labor.
[I suspect this will go away as soon as warmer weather returns].

The other issue seems like an intermittent problem. Maybe something was left loose when the battery was replaced. There is a direct wire from battery to the starter as well as the alternator. Check the far ends of the cables from the battery.

Salim

Before putting a wrench on wires, please follow the safety things I mentioned in my previous note.
Make sure the vehicle is turned off for about 2 mins. Remove the key fobs away.
Negative terminal is the first one that comes off and the last one to put back on.

 

Briefly, the problem I have is the “Key Not Detected” light comes on whenever the rear passenger door is opened and closed. (The rest of what is below is just insights, in case they related to the “Key Not Detected” issue.) I can get the Key Not Detected light to go off by turning the car off and then restarting.

Details: This is a one-owner car that has never given me any trouble. Also, I changed the batteries in both key FOBs to no avail.

The problem began when I replaced the car battery. (I have replaced this battery several times before with no problems.) It was suggested that I go through the process of removing both FOBs from the vicinity of the car; disconnect the negative terminal on the battery; wait 20 minutes, then reconnect the battery’ Some memory features were lost (e.g., radio station presets), but this seemed to fix the problem!

This may or may not be related; however, I let the car sit a few weeks without starting it in cold, winter weather. When I went to start it, it seemed the starter turned but didn’t seem to turn the engine, just a whining noise (not clicking like a dead battery). I pushed the Start button again and this time the motor turned over and soon started, albeit roughly, then it quickly smoothed out, running fine.

So, I drove to pick up my grandson and when he got in the rear passenger door, the “Key Not Detected” warning came on again (when he ‘slammed’ the door shut). Back home, I went through the whole reset process mentioned above and it seems to work… for all doors except when the rear passenger door is opened and closed. Again, if I turn the car off and on again it remedies the problem temporarily, until the rear door opens and closes.

It seems I read somewhere that there may be something in the door(s) that may be the culprit (actuator, oscillator???) but I can’t find that information anymore.

Any thoughts or suggestions?

 

There are indeed still shops that refurbish factory starters and alternators (which is what I prefer to do). Last March I had the factory starter in my trusty 1999 Ram refurbished with the proper kit for about $80. Less costly than purchasing a new one, and I am guaranteed a perfect fit.

That same shop refurbished the factory alternator in my wife's 2006 Jaguar XK8 with the proper kit in July 2018 for about $120. Again, less costly than a new one and guaranteed a perfect fit.

 

Thank you!