Time for a new CAS

Bouncer · 03-12-2026, 05:02 AM

09' e93.

Sigh.. so bit of a stumper.

I'm trying to figure out if I need to replace the CAS box or not. I have comfort access and two keys. Batteries in keys replaced, symptoms persist across both keys.

Symptoms:
Sometimes remote key works, sometimes not. Typically in the morning the remote unlock works, but doesn't work the rest of the day. Sometimes if the car sits for a few hours it will work again once, but not after that (unless the car sits for some more hours).

IF the remote fob works (typically in the morning) then the system remembers the radio settings etc for the key. If the remote key is NOT working (later in the day) all that information is gone and the radio presets aren't present.

Remote fob access (for starting) doesn't work in the mornings and the key must be inserted in the dash. Inserting and removing the key three times into the dash mount and the car will then fully turn on and start. First two times, it will not, though the dash partially comes on (like stage 1 power). For the rest of the day, it typically turns on and starts on first key insertion (and usually key can stay in the pocket).

It *feels* like the car is cycling between "remembering" the key and not. And needs time for something to reset or a ground to clear for the system to recognize/accept the key fob. Then when it's defaulted by inserting the key X number of times it will power on and start, but doesn't accept the remote signal/code again until it cycles after a certain amount of time sitting.

I'm considering replacing the CAS module or possibly the actual key point in the dash (or theoretically the mirror module, but it seems to function fine with dimming and the ompass etc). The only codes I'm throwing are:

2DED: 0x2DED power management, closed-circuit monitoring

D904: K_CAN_Leitungsfehler
A0B8: Hallsensor_RAST_KS

Any ideas? Kinda tearing my hair out here and I don't have a lot to spare!

Second question:
If I do need to get a new CAS, can I code it with INPA or do I need to send it to a specialist, and if I need to send it off to be coded (along with a key I'd guess) am I still able to start the car or what?

ctuna · 03-12-2026, 07:28 PM

The general forum is more likely to give you response on this than the stereo sub forum .

03-12-2026, 05:02 AM	#1
Bouncer Carpe Cookius! 25 Rep 29 Posts Drives: 09' 335IC Atl Bl. Wtr Metallic Join Date: Jul 2014 Location: United States iTrader: (0) Garage List 2009 BMW 335i Conve ... [0.00]	Time for a new CAS 09' e93. Sigh.. so bit of a stumper. I'm trying to figure out if I need to replace the CAS box or not. I have comfort access and two keys. Batteries in keys replaced, symptoms persist across both keys. Symptoms: Sometimes remote key works, sometimes not. Typically in the morning the remote unlock works, but doesn't work the rest of the day. Sometimes if the car sits for a few hours it will work again once, but not after that (unless the car sits for some more hours). IF the remote fob works (typically in the morning) then the system remembers the radio settings etc for the key. If the remote key is NOT working (later in the day) all that information is gone and the radio presets aren't present. Remote fob access (for starting) doesn't work in the mornings and the key must be inserted in the dash. Inserting and removing the key three times into the dash mount and the car will then fully turn on and start. First two times, it will not, though the dash partially comes on (like stage 1 power). For the rest of the day, it typically turns on and starts on first key insertion (and usually key can stay in the pocket). It feels like the car is cycling between "remembering" the key and not. And needs time for something to reset or a ground to clear for the system to recognize/accept the key fob. Then when it's defaulted by inserting the key X number of times it will power on and start, but doesn't accept the remote signal/code again until it cycles after a certain amount of time sitting. I'm considering replacing the CAS module or possibly the actual key point in the dash (or theoretically the mirror module, but it seems to function fine with dimming and the ompass etc). The only codes I'm throwing are: 2DED: 0x2DED power management, closed-circuit monitoring D904: K_CAN_Leitungsfehler A0B8: Hallsensor_RAST_KS Any ideas? Kinda tearing my hair out here and I don't have a lot to spare! Second question: If I do need to get a new CAS, can I code it with INPA or do I need to send it to a specialist, and if I need to send it off to be coded (along with a key I'd guess) am I still able to start the car or what?
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03-12-2026, 07:28 PM	#2
ctuna Lieutenant General 2438 Rep 14,067 Posts Drives: 325xi 06 wagon MT Join Date: Jan 2010 Location: Santa Cruz, Ca iTrader: (0)	The general forum is more likely to give you response on this than the stereo sub forum .
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