[sdeprima]

I was looking at my service info on the dash today because I have a service appointment later this week and I was realizing that most of the scheduled servicing icons would fall outside of my warranty period by date and/or mileage count. For example, the spark plug icon says 26,000 miles, which I assume means they need to be changed when that mileage reaches zero, but I am out of warranty in a little over a year and there is no way I will drive that much. The truth is, everyone of the icons in my service info except the brake fluid flush and air filter have not appeared at all and will not appear until my car falls out of warranty according to my cars service info. Is this normal? Is there no set maintenance schedule to go off of? 15,000? 30,000 mile checkup? I just don't understand how there is a free maintenance plan if there is no set plan to go off of? According to my car, I require basically zero maintenance until I am out of warranty, or am I misunderstanding something here? If anyone can explain I'd greatly appreciate it because I feel like my car should be due for some scheduled maintenance at some point.... cheers

[-=Hot|Ice=-]

It is condition based. If the car senses it needs it, it'll tell you. It all depends on how you drive.

[pruettfan]

There are several ways the service intervals work. Several are based on time and miles. Some are based on condition. These are oil and brakes. The brakes have wear sensors that measure pad thickness and then that is converted into an approximate number of miles till they have to be changed. Oil is calculated on time, temp and driving conditions. In the summer in AZ my oil life drops quicker then in the winter due to temps as an example. I believe the air filters are based on miles but the cabin filter may be based on some other calculation. Brake flushes I believe are based on time. The maintenance plan is simple for BMW. When your car tells you it needs to be serviced they will service it for free during the warranty period. Some cars will need slightly more or less service in the warranty period based on miles.

As someone outside of the warranty period I love the condition based service concept. It saves money on maintenance and if you have I-Drive it is very easy to see what needs to be done when

[Ryan323i]

Free Maintenance Plan = wiper blades, air filters, 2 brake fluid flushes and a few oil changes. The intervals on other services were increased to lessen the overall cost to own. While the intervals in the CBS are good for the most part, I don't agree that some of the fluids are now considered "lifetime", especially if you're someone who plans to keep your BMW for a long time.

[742]

“free service” for me was two oil changes and a brake fluid flush. Joy. Oh, and a set of wiper blades.

However I don’t think that this is an evil plot by BMW as much as it is marketing pressure from the cost to own statistics compiled by JD Power/CR & company. The system that they have created favors a car and program under which minimal maintenance is done for 100k/5years, even though that reduces the vehicle’s service life. The manufacturer who has a serious maintenance program will be severely penalized in the market place.

[noro]

Originally Posted by pruettfan

The brakes have wear sensors that measure pad thickness and then that is converted into an approximate number of miles till they have to be changed.

I don't believe the sensor actually senses the thickness. The brake sensor senses when the brakes are toast, it's just a wire get broken when the pad is at its lowest level and sends a signal out. I am assuming that the light is either determine by your driving style on just time/mileage. I know mine came up a few times and it was bogus, pads where fine.

[sdeprima]

So it seems that most of my servicing like changing my spark plugs is going to come out of my pocket....that's a bummer

[noro]

Originally Posted by sdeprima

So it seems that most of my servicing like changing my spark plugs is going to come out of my pocket....that's a bummer

Spark plugs are 8 bucks each, a good repair manual is 50, socket and wrench set is ~20.

...the feeling of job done yourself, priceless!

[ENINTY]

Originally Posted by noro

Spark plugs are 8 bucks each, a good repair manual is 50, socket and wrench set is ~20.

...the feeling of job done yourself, priceless!

The plugs are $17 each at Tischer. Bently is $90 at Amazon. Proceedure is a PIA: remove cabin airfilter housing, cowl tray, engine cover, 6 coils (carefull don't break the connectors), then you get to the plugs. (Blow the plug holes out with compressed air to make sure no dirt gets in the cylinders before you remove the plugs). Torque to 20 NM (need a torque wrench). Put the parts all back together. Oh, and make sure you get the cabin airfilter box sealed correctly, or it will leak water and toast the blower motor...

Then the feeling of a job done yourself.

[MrDummy]

Originally Posted by noro

I don't believe the sensor actually senses the thickness. The brake sensor senses when the brakes are toast, it's just a wire get broken when the pad is at its lowest level and sends a signal out. I am assuming that the light is either determine by your driving style on just time/mileage. I know mine came up a few times and it was bogus, pads where fine.

This would make total sense from what my bimmer is doing.

6mm of pad in the front yet the CBS indicator says I have 4800 miles left.
8mm in rears and the CBS says I have 35,000 miles left.

Something is fishy. as my dealer said that the light doesnt come on until the pad hits 3mm of thickness left.

So they told me to ignore the mileage readings and just wait until the yellow light pops on for brake service.

[F32Fleet]

spark plugs? What's spark plugs?

In the E46 days BMW did have a Inspection I and II. These were mileage based but TBH I don't remember it as being all that much different from the current set up.

[MrDummy]

Hey Socom, do you know if what I stated in my post is correct or HOW the brake sensors REALLY work.

I will continue to search but so far no luck yet.

[cb1111]

Originally Posted by MrDummy

Hey Socom, do you know if what I stated in my post is correct or HOW the brake sensors REALLY work.

I will continue to search but so far no luck yet.

The sensors merely alert once they come into contact with metal. The "miles to replacement" seems to be a mathematical formula based upon driving style. Mine started at ~36k miles and are now showing replacement due in 46k miles (for a total of about 70k miles - about when my Audi brakes were due for replacement)

There are a few items that are only time based - like brake fluid changes. Most everything else is condition based - i.e., the car will calculate (based on your driving style) when service is due. This includes oil changes (usually between 15 & 18k miles) and the like. Some items are due every x# of oil changes (some filters for example)

Finally, on the 335 only, there is on item that requires replacement based only on mileage - the HPFP every 3-4k miles

[MrDummy]

^^^ THANKS a TON my friend, that helps me out 100% and would explain everything.

So if I feel better now knowing with the pad and tire tread thickness I have currently I should NOT need any of these items for a while then. (Since I do a ton of Highway driving)

P.S. Do you know what the mm thickness is on brand new pads by any chance?

Carry on...

[ENINTY]

Originally Posted by MrDummy

Hey Socom, do you know if what I stated in my post is correct or HOW the brake sensors REALLY work.

I will continue to search but so far no luck yet.

We discussed this a few years ago, but it is worth revisiting. (BMW changed the brake sensor system from the original system they used for years where the sensor wore to a point that it indicated the pad was at its minimum thickness.) The wear sensor works on the principle that as the plastic body wears away it exposes a copper wire loop that eventually breaks and opens the electrical circuit running through the sensor, which in turn lights the pad-replacement light on the dash.

Now that the BMWs have a Conditioned Based Service (CBS) system that gives an estimated mileage of when the pads will need to be replaced, BMW made a change to the system. It pad wear sensor is now dual-stage. That means it has two loops of copper wire (one in front of the other). The first loop breaks and the CBS computer takes note of the date and mileage on the car. The computer then uses an algorithm to calculate the estimated calendar date and miles when the pads will need to be replaced. Once the second wire loop breaks, the pad replacement light on the dash is illuminated until the pads and sensor are replaced.

The CBS reminder notification needs to be manually reset in the same manner as an oil change, or other service reminder.

[MrDummy]

^^ see I have no date though for my pads replacement just the mileage countdown.

Plus would this be in all bmws?

Cause that would again make me re-think why my fronts which have 6mm of pad left per inspection but shows 4800 miles left on CBS. But rears have only 2 more mm's of pad but it shows 35,000 miles till service would be needed.

almost a 29,000 mile difference for 2mm seems a lot to me?

But maybe I am just a Dummy?

[ENINTY]

Originally Posted by MrDummy

^^ see I have no date though for my pads replacement just the mileage countdown.

Plus would this be in all bmws?

Cause that would again make me re-think why my fronts which have 6mm of pad left per inspection but shows 4800 miles left on CBS. But rears have only 2 more mm's of pad but it shows 35,000 miles till service would be needed.

almost a 29,000 mile difference for 2mm seems a lot to me?

But maybe I am just a Dummy?

Your are trying too hard. Just ignore the CBS messages regarding your brake pad life. When the pads reach their limit, the icon on the dash will light and stay lit, telling you either the front or rear pads are in need of replacement. You have plenty of time, several 1000's of miles to get the pads replaced. It's not like the indicator comes on and you instantly need to replace the pads. They still have a margin of safety to remain effective at stopping the car.

[MrDummy]

^^ thanks for being polite and very informative(I mean that non sarcastically). I will do just that, I was just curious as I like to guestimate when things will need to be fixed or serviced so I can budget the money for said repairs.

But if I can get another year out of the pads I guess I will be very happy.

Thanks again.