Update!: "Chassis Malfunction"

[chillindrdude]

subscribed for updates...

this is disappointing.

[MaynardZed]

Originally Posted by brian99997

This has to be specific to certain cars.. mine is sideways near daily with no trouble other than a white car shows tire debris quickly.

Not really the same thing. Mine only does it on the track. Wondering if heat has something to do with it if those sensors go wacky if they are close enough to the rotor assembly?

As gthal said please take your car in and get the codes pulled. At least it will be documented for when it reoccurs.

[Roychimac]

I just dropped mine at service today and the faults read were vertical acceleration sensors and "front of car height too low". I know the car isn't too low cuz we only dropped it .75 in the front which is the same as what we dropped in the rear with my KW HAS kit.

They're going to replace the 2 sensors up front first to see if it fixes it and then do a re-initialization.

I'll keep you guys informed.

[M3SSY]

I wonder if you are creating slip angles greater than the car can calculate for and you're getting some sort of variable over run or similar...

[brian99997]

Originally Posted by MaynardZed

Not really the same thing. Mine only does it on the track. Wondering if heat has something to do with it if those sensors go wacky if they are close enough to the rotor assembly?

Lots of track time although my tires don't allow for much slip angle and I haven't fully spun the car yet so going back to Jeremey Clarkson, he must have been resetting something :P

[MaynardZed]

Originally Posted by Roychimac

I just dropped mine at service today and the faults read were vertical acceleration sensors and "front of car height too low". I know the car isn't too low cuz we only dropped it .75 in the front which is the same as what we dropped in the rear with my KW HAS kit.

They're going to replace the 2 sensors up front first to see if it fixes it and then do a re-initialization.

I'll keep you guys informed.

Thanks, keep us posted. Currently my car has 265/35/19 front tire on stock springs so actually higher than normal and still got the malfunction.

Originally Posted by brian99997

Lots of track time although my tires don't allow for much slip angle and I haven't fully spun the car yet so going back to Jeremey Clarkson, he must have been resetting something :P

Thought you were talking about street driving. What tires are you using?

[M3NetNerd]

Just to document I am running 275/35/18 square for tires on the track.

[135pr]

My m4 have h&r sport suspension, no adaptive suspension on stock tires and when a go to the drag track I get the message. "Drivetrain malfunction". I stop the car, turn off and the code was cleared.

I will go to services department and let you know what happens.

[135pr]

Originally Posted by darge82

Is your car bone stock or tuned? Drivetrain malfunction is different then a Chassis malfunction. Drivetrain malfunction is more related to engine/engine electronics and transmission. Chassis malfunction is related to suspension and stability stuff.

Thanks for the info. My car have JB4 and downpipe.

[MaynardZed]

Originally Posted by Railgun

So, an FYI, there were a bunch of M3/4s on track at Brands Hatch this past week with a local dealership that had setup a track day. Not one that I'm aware of had any issues relating to this. There were also three demos, M3 and M4 coupe and vert (among other Ms) that were being driven by Tom Chilton, and other than giving them a break every 30 min or so, didn't have any reported issues either.

The only issue mentioned, by Tom, was that even with DSC disabled, it still eventually would reel things in if you get too extreme.

It could be a larger issue, but it also may simply be specific to you car. It happens sometimes unfortunately.

Good to note. Wonder if they were running stock pads and tires though? My current theory is that it's heat related in regards to the proximity of the front strut sensors. Possibly the R-comps are Carbotech XP12 pads are generating enough heat through the rotor/hub to make the sensors fail? My front calipers turned green from heat and it's also quite warm here in Phoenix.

Nevertheless, if all DSC is turned off it should never intervene. Not understanding that for Tom, unless you mean he was running MDM (Euro?). The U.S. MDM mode is too intrusive to be used on the track, so I runn with everything completely off.

I know another member that runs Carbotechs, but I believe he was smart enough to disconnect the EDC sensors for his track day. This may be the temporary solution until the problem is figured out definitively.

[gthal]

Originally Posted by MaynardZed

Good to note. Wonder if they were running stock pads and tires though? My current theory is that it's heat related in regards to the proximity of the front strut sensors. Possibly the R-comps are Carbotech XP12 pads are generating enough heat through the rotor/hub to make the sensors fail? My front calipers turned green from heat and it's also quite warm here in Phoenix.

Nevertheless, if all DSC is turned off it should never intervene. Not understanding that for Tom, unless you mean he was running MDM (Euro?). The U.S. MDM mode is too intrusive to be used on the track, so I runn with everything completely off.

I know another member that runs Carbotechs, but I believe he was smart enough to disconnect the EDC sensors for his track day. This may be the temporary solution until the problem is figured out definitively.

Is there something about the Carbotech pads that causes more heat to transfer into the rotor/hub?

[MaynardZed]

Originally Posted by gthal

Is there something about the Carbotech pads that causes more heat to transfer into the rotor/hub?

They can tolerate much higher heat overall (than stock pads) so just theorizing that maybe the heat of the wheel assembly is somehow messing with the sensors? My front rotors would sometimes be billowing out surprisingly heavy looking smoke after a session with the carbotechs, not just light smoke like I've seen with other cars I've tracked.

I'm not sure where these sensors are? If they're at the top of the strut, seems that they should be far enough away to not be affected by the heat? Also, the other member that had this issue on track was at an autocross, so don't think his rotors would've gotten that hot with the short session? I guess I'm just grasping at straws while my M4 sits at the dealer for the third time for this.

Hopefully they've got some better ideas than I do!

[smh_amg_m4gts]

Planning to take my M3 to Laguna Seca in June. No mods. Stay tuned.

[smh_amg_m4gts]

Sorry if I missed this, but are folks seeing this issue with DCTs or Manual transmission?

[FTS]

Originally Posted by MaynardZed

They can tolerate much higher heat overall (than stock pads) so just theorizing that maybe the heat of the wheel assembly is somehow messing with the sensors?

I'm not sure where these sensors are? If they're at the top of the strut, seems that they should be far enough away to not be affected by the heat?

I highly doubt heat from brake system has anything to do with this, but obviously anything is possible at the end. The total heat absorption capacity from pad to pad won't change if they are the same thickness.

The sensors are up top btw, if you lift the rubber covers from the strut tops, you'll see the them, the harness is exposed outside of the covers also.

[MaynardZed]

Originally Posted by stunnaM3

Sorry if I missed this, but are folks seeing this issue with DCTs or Manual transmission?

Could happen to either, not associated with the driveline, but the chassis / EDC system supposedly. Only been 2 cars on track that have done it that we know of. A few others claimed chassis malfunction after doing spring swaps. Not sure if related.

Originally Posted by Railgun

I had explicitly asked that. DSC was off. Not MDM mode. And they were running standard brakes with stock pads, no CCBs.

Interesting, not sure what was intervening then?

Originally Posted by FTS

I highly doubt heat from brake system has anything to do with this, but obviously anything is possible at the end. The total heat absorption capacity from pad to pad won't change if they are the same thickness.

The sensors are up top btw, if you lift the rubber covers from the strut tops, you'll see the them, the harness is exposed outside of the covers also.

Ok, seems implausible heat is the issue. Should be easy enough to disconnect though. Can't check for myself since I don't have my car. Radio silence from dealer.

[MaynardZed]

Got the call that my car was done. They ended up replacing the right front strut and right front sensor again. Speaking with the SA when I picked it up, he said they replaced it, because that's what engineering wanted them to do. The faults that the sensor is throwing are "plausibility faults" which, when I inquired, means that "they don't know why its throwing the faults". Their latest theory is that the track tires somehow send the strut/sensor out of "bounds", but when he continued on to say "maybe they skip/skid more than OEM tires" I dismissed that theory since the R888 are much stickier actually.

I don't want to sound too critical of the dealership. Sometimes the hardest thing to do is to say "we don't know what is wrong" which that is basically what they are doing for now. The dealership has put in a lot of effort trying to figure out what exactly the issue is, but unfortunately it seems to be above their knowledge base to found the answer. A "PUMA" case has been started and they still are encouraging me to track the car more so that it might help them find an answer. Even mentioned maybe having a field engineer go with me to the track, but surely blowing smoke on that.

Anyway, happy to have my car back. I might test it at an early morning test and tune on June 20th, but really nothing much going on here in Phoenix for the summer with the heat.

[JoeFromPA]

So I'm noticing that in the three instances reported in this thread we have:

1. Non-stock tire sizes + track tires
2. Non-stock tire sizes
3. Lowered ride height

And on the other hand we have hundreds of stock m3s being tossed around tracks for almost a year now with no related stories that I know of...

[MatthewDavid]

Seemingly related perhaps have any of you also noticed how weak a constitution the cruise control now has in corners? I used to take a corner on my commute at 75 mph in my E92 and the F82 now wants to drop 10-15 mph. It's weird how sensitive this car is to roll. Obviously you wouldn't use cruise at the track but it is indicative to how sensitive the stability sensors seem to be for this car.

[MaynardZed]

Originally Posted by JoeFromPA

So I'm noticing that in the three instances reported in this thread we have:

1. Non-stock tire sizes + track tires
2. Non-stock tire sizes
3. Lowered ride height

And on the other hand we have hundreds of stock m3s being tossed around tracks for almost a year now with no related stories that I know of...

Yes, hopefully isolated cases. Seems as if they are pointing towards my track tires as the culprit, but honestly I think they are just reaching for answers there. They also asked if I left the ignition on when I trailered my car to the track. I just drive the M4 to the track, of course.

BTW, I think very few F8X have been tossed around the track extensively with the stock Michelin PSS. They have almost universally been deemed as a poor track day tire by anyone above beginner level.

[RocketBoots]

Originally Posted by MaynardZed

A "PUMA" case has been started and they still are encouraging me to track the car more so that it might help them find an answer. Even mentioned maybe having a field engineer go with me to the track, but surely blowing smoke on that.

Take 'em up on the offer to have the engineer ride shotgun on the track

Of course, just because he is there with you, the error will not happen.

Good they did the PUMA; seems like they're taking it to the next level

[giantkeeper]

Originally Posted by MaynardZed

I might test it at an early morning test and tune on June 20th, but really nothing much going on here in Phoenix for the summer with the heat.