Active Steering

[cape]

I have a 2006 650i and just recently a system notification has started coming and going - Active Steering Malfunction. Hoping that this can be cured simply, is there active steering fluid that might be low or do I need to have athe dealer take a look?
Also, the car seems to be riding a little harsher and louder - are those signs of tire replacement time?
Thanks in advance for comments

[cobradav]

Active steering (also active roll stabilization if you have it) uses Petrosin CHF 11S hydraulic fluid. Should be reservoir on left side of engine bay as you look in from front and it has the CHS 11S molded on the top cover. However, that is on my MY05 with 4.4L engine. They could have moved it on the 4.8L engine you have. I’ll check my repair manual tonight. If you have kindly dealer he may just top it off for you. Otherwise, you could do as I do and buy a quart and just keep in car for such times, although I really have not used that much in 108k miles. Now obviously this is not the only possible problem. Active steering relies on multiple sensors, especially associated with the wheels and also the steering angle sensor (SZL) in the steering column. However, if you have no other warnings it could just be hydraulic fluid level.

As to your ride. What do the tires look like? How many miles on them? What type, OEM RFT or are they non-RFT? Louder is often the sign of wear, but harsh ride is not, at least in my experience. I have been through (well soon the third set) three sets of RFTs and 2 sets of non-RFT. Truthfully, I have only replaced tires due to visual wear indications (always rears worst). My RFTs have never done less than 20K miles and usually closer to 25k miles. My PS2s and PZeros sets could not even reach 20k miles. But I really did not notice ride or noise change. Grip, heck yes, I noticed that change, especially in the wet.

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US '05 645 Coupe|Silver Grey|Chateau|Sport|Logic 7|HUD|Cold Pkg|SAT|AUX|BT w/ snap-in adapter|MP3|V1|CIP 31.00.00


www.bimmerdrivers.com

[cape]

Thanks for taking the time to check on the location of the 4.4L reservoir - and I have not gotten any other warnings.
As for tires, I still have the original OEM Bridgestone RFT's. The tread wear looks fine (to me and a neighbor who is a longtime and knowledgeable BMW owner)- and I'm at 45K miles on the first and only set.

[cobradav]

WOW on the miles - unheard of in my experience. I would replace them just because they are OLD. I assume you have staggered setup for the sports package, correct? That is just simply amazing. Do you have any curved roads where you live? Even my predominatly highway miles could not stretech the rears past 30k if I never made a turn at all.

I noticed neither owners manual (MY05 or MY06) shows the PS resevoir as if BMW does not want you in there but that never stopped me.
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US '05 645 Coupe|Silver Grey|Chateau|Sport|Logic 7|HUD|Cold Pkg|SAT|AUX|BT w/ snap-in adapter|MP3|V1|CIP 31.00.00


www.bimmerdrivers.com

[cape]

Yes, staggered set up and I hear you on the tire change. I'm on it and thanks for the time.