Very, very, strange issue here and not sure what could be the issue. Today I changed the serpentine belt on my 2004 Mini Cooper S. So to do this I jacked up the passenger front and removed the tire and inner fender, then removed and replaced the serp belt. The wheel speed monitor was hanging so I placed it in the spot where it is suppose to go, it clipped right in. So, after putting it back together I drive the car and all is good at first, like it should be and like it was before, the car was running perfect just time for a belt. No issues with the car before changing the belt, but I get about a mile down the road and the engine light comes on and then the DSC light. It still runs fine then all of a sudden the engine light starts to flash and it starts to sputter. It still runs but definately missing after a few miles. Ok, so I take it to Autozone and the guy there tells me he has seen a few minis have the same issue after jacking up the car. Very strange to hear this cause it makes no sense to me. Ok, he clears the lights and it seems all is good, full power and no lights, but then a mile down the road both lights come on again. So I call the service department at mini and he tells me the only thing he can think of is the wheel speed monitor to cause both lights to come on at the same time. So, I pull it apart again and check all the wires to the speed sensor, cause like I said I clipped it in cause it was just hanging before, but it is definately in the proper place and all wires look good. Not sure why it would just go bad but I'm wondering if anyone has had a similar problem after jacking up their mini? My first thought was that I only had about an 8th of a tank and maybe I stirred up some trash or something in the gas tank when I jacked it up, maybe caused the fuel filter to get trash explaining why it comes on after a mile or so when the light is cleared, after running good before the lights come on. Anyone have a similar issue and did you find a solution? Thanks

 

What were the codes he pulled?

 

P0300 was the code Autozone pulled. The service guy at Mini told me the code they pull doesn't mean anything to them, thats when he suggested the wheel speed monitor to me. Here are the definitions they printed for me:

Random cylinder misfire detected

Explanation:
Lean Air/Fuel ratio

Probable cause:
Ignition system misfire condition
Fuel injector fault
Engine mechanical condition


So, going back to my original idea of maybe I sucked up some trash from the gas tank after jacking it up seems like a possible, any part going bad doesn't seem possible considering I really didn't do much to the car, that's what has me confused.

 

Not all things are connected....
I guess it is possible the belt was slipping so much, that the new belt is allowing the sc to make so much more boost, that the car is suddenly running a bit lean...
If that is the case, the problem can be corrected two ways...
Driving it will allow the computer to adjust the fuel trims...
Resettting adaptations....needs a pretty good factory level odb2 tool....

 

I was considering the driving to reset it, any idea how many miles before it should reset? The funny thing is I had autozone reset it again and lights went out. I drove it down the highway at full speed for about 5 miles with no lights and no issues. I parked the car, and about 30 mins later drove it about a mile and lights back on. First the engine light comes on solid. Then the DSC light. It still runs fine. But then the Engine light flashes a few times and it starts to miss. Very strange to me that it is not missing from the moment I start it?

 

Ok. Short distance through my neighborhood and the DSC light comes on then the engine light flashes and it goes into limp. I decide to get it up to speed and put some miles on it to see if it will reset. I turn the car off before getting on the highway and restart the car. The only light on is the engine light solid. So I drive it on the highway for almost 40 miles around 70 miles per hour and it runs good with no lights except the solid engine light, the other lights never come on. I am going to let it sit a little then drive it again through stop in go traffic to see if fixed, on the highway it is good, but it was like this yesterday but I only did about 5 miles on highway, so I guess we will see on the next drive.

 

The flashing light is typical of WHEN the misfire is occurring...
You look at the wires? The fact it seems to run better when pushed hard is a bad sign....points to an actual compression issue...
Might just be you had the misfortune of changing the belt at about the same time your issue started... Did you fiddle with anything else?
You did fill up your gas tank right? Used 90+ octane right?
There are 2 filters...a regular filter in the tank...it is huge...blockage would result in less powercst rpm..
If some gunk got beyond that somehow...there is a tiny "micro" filter on the fuel rail...

 

The strange thing is the order of the flashing light, it comes on AFTER the DSC light comes on. So makes me wonder if the DSC is causing the misfire somehow, putting it into a sort of limp mode? Didn't do anything else to the car, added gas treatment and half a tank(didn't want to fill up completely cause probably going to change fuel filter which I see is on top of the tank). I don't see the micro-filter do you exactly where I should be looking to find it, cause when I search online for it can't find reference to it. But that being said I'm not sure if it is fuel related or if related to the DSC? Thanks

 

Seems like the dsc light comes on when it's seeing the misfire but they aren't bad enough or there aren't that many yet. If you had a code scanner you'd see it would find a pending code. Once there are enough it throws the code and you go limp.

Have you checked your coil, wires and plugs?

Have you checked there are no vacuum leaks? Possibly the green gasket? Intercooler boots?

Get a compression test done and have the engine smoked to see if there's leaks. Also have the fuel pressure tested.

 

One thought....
When my hot side t-map was failing, the car would give a studder, kinda felt like a miss...the DSC light would come on...and sometimes no code...sometimes the code would appear at restart, and the DSC light would stay off for a mile or so...
Sometimes the DSC light would come on as soon as I started the motor if reset the code that would SOMETIMES appear...guessing the computer saw invalid data and could no longer plan on using the DSC features, and would toss up the light, but would run OK some of the time...
But just bringing this up to be 100% sure you have a code that you read recently...not just the feeling that it "feels " like a miss still...but never a "limp mode"...
But did get a odd code a limp once when my intercooler boots were not back on perfectly.... Does not really matter, but just bringing it up so you keep your eyes open when you look under the hood...
Heck. Bump a vacuum line maybe when using the belt tensioner? Kinda teaching here trying to help connect the two (running issue and belt change) so it can be ruled out as a distraction, or ruled a cause...
Good luck...keep us updated. Sucks when a " simple" mini job turns into a heck of a week.

 

The "micro" filter is basicly on the fuel rail...by the fuel pressure regulator...another thing to look at since the tiny vacuum line attached to it can get dry and brittle...then can, leak, fall off...
Not sure why it would have just started... Guess if you lowered you car HARD, it could have jostled something...

 

Yeah a bit confusing why just started but maybe getting closer as to where you are thinking as far as bumped something when changing the belt. Like I said in the original post the wheel speed sensor was just hanging freely so I attached it to the proper clip. I keep thinking it has to be related and now thinking this a little more because the car will idle in place fine, I can rev it fine, and as long as I do not move the car the DSC light does not come on and the Engine light does not flash as well as does not seem to have any miss. I just keep thinking that the first thing that happens when driving it is that the DSC comes on a little ways down the road and then the engine light flashes and it seems to go into a limp mode, but only after the DSC comes on. So, if the wheel speed sensor can create the DSC coming on, maybe there is a fault in the wire to his and when I moved it into the proper location it is causing the problem to occur. Not sure but going to get it back up in the air and recheck the connections and wires to the speed sensor and anything else near the belt. I just don't see it being fuel or electrical related to the engine given the fact it will run in place fine, just acts up driving. Will update. Thanks

 

I think it has to be related to the wheel speed sensor because I can create the same issue with the car at an idle by disconnected the wheel speed sensor. When I disconnect the sensor, the DSC light comes on, the engine light flashes a few seconds later and the car starts to miss. So I guess I am going to get the sensor and go forward from that point.

 

Wheel speed sensor causes car to misfire? It must be the other way around. Misfires can cause the DSC light to turn on. Hunt down the misfire cause...ignition, vacuum & fuel distribution are what I would check 1st.

 

A few things that really makes no sense in regards to a misfire is that the car ran perfect before changing the belt. Only thing besides the belt I touch was the wheel speed sensor, like I said in the original post I clipped it in the proper location as it was just hanging before. Also, as I said in the other posts is the car will sit and idle, rev, and anything else perfectly with no misfire, but I can create a misfire by unplugging the wheel speed sensor, this is the only time the misfire will occur if I do not drive the car. Which I would think the car sees a fault in the DSC and puts it into some sort of Limp mode. I can drive it in a straight line without braking down the highway for 30+ miles as well and no misfire. The only time it starts is after stopping a few times in town driving, happens within a half mile of my first stop and go. So, if it was a fuel, vacuum, ignition related item why will it not have any issues running while sitting still or driving in a constant speed? This means that at idle or at rev while sitting still or changing RPM's, even if I press the brakes, which would simulate driving except for the wheels actually moving it runs perfect, no misfire and no DSC or flashing light? As I said in the original post when I did call Mini and told the service tech there about how the engine light was solid, then after driving the DSC light would come on, then within a few seconds the engine light would flash and it would lose power, he told me the only thing he could think of was the wheel speed sensor. It didn't make much sense to me either, cause Autozone told me it was reading a random misfire code, but then again the guy at mini told me that what they read will not be the same codes at mini, so he didn't even want the codes. All I know is the car runs perfect in the conditions I say, so if it was a vacuum, ignition, fuel related problem you would think that by idle, rev, or driving the misfire would occur, but it doesn't occur. It will only occur after the DSC light comes on, and I think by disconnecting the wheel speed sensor while the car is at idle and the same problem occurs it leads to believe it is the wheel speed sensor maybe putting the car into a limp mode? It makes no sense to me either as I am mostly a domestic car person and not a whole lot of experience with the mini so learning as I go that they seem pretty touchy. Can get the speed sensor on Ebay for about $15 so may be my least costly attempt, as I'm about ready to bring it to mini to get diagnosed. I did pull the plugs and they all looked good but went ahead and put a new set in, this made no difference, still ran fine sitting but after moving the same issue occurred. I don't know why the wheel speed sensor could cause the issue but the mini guy first made the suggestion before I even knew that was the sensor that I had clipped into place, so it seems to make some sense, just don't know why the car would not run at full speed just for the DSC.

 

You realize you can turn the DSC off right?
Just flip the switch up...will effectively be off for all non track purposes...it will not cut engine power as it sees any issues.
And a DSC FAULT LIGHT cannot CAUSE a misfire....
And the $15 sensors are called junk by 50+% of the folks that try them...so likely wasted $$.
Simply put....you could turn off the DSC, and drive the car indefinitely, without issues...so think you are thinking of the DSC/misfire issue backwards.....
Think about it this way...
The cars engine management software sees a "pending code" and likely disables the DSC...then when it "confirms" the code , throws a light, code is set to memory....
DSC is a ADD ON MODULE...
If you pinched or cut a wire on the sensor, the DSC COULD missense a tire that it thinks is stuck, and cut engine rpms for a few moments till it sees the wheel speed sensor move...then give you the power back...no engine code, and the DSC light WOULD FLASH....THEN GO OUT.
with limp mode, the EML/check engine light will light...and rpms, power, etc will drop...TILL THE CAR IS TURNED OFF AND RESTARTED.

 

I just got off the phone with another mini dealership service tech and he told me pretty much the same thing as the other dealership. He says yes the DSC can cause the car to go into a limp mode, and that a faulty wheel speed sensor can cause this issue. Almost everything I have read on mini forums and in the manual say that when you disable the DSC it will not create power loss, but it doesn't specifically say whether a fault in the DSC system will create a limp mode. Also both techs have said a speed sensor would be their first assumption and that it can cause limp mode, but of course it would need to be diagnosed by them to find the exact issue. They both say that Autozone cannot see the specific codes related to tracing the problem in the DSC, they are only going to be able to provide a generic code. So I guess I'm either going to have mini read it or find a good indy shop to do so. I appreciate all the help and after I get it scanned and find a solution I will post that here so hopefully it can be of some future help to someone.

 

Rich99. I have been having the exact same problem you described for the last few days. Same code po300, same dsc light. I will update my troubleshooting progress here. I'm going to go unplug my wheel sensor in the morning and see if i can duplicate this intermittent problem. After i clear the code, my car will run perfect for a while, could be 5 miles could be 30 miles then the problem comes back. I can get it out of limp mode by turning off ignition, then restarting. The car has good power, good fuel economy (30mpg). So far my troubleshoting has been to check for vacuum leaks, checked plug wires and cleaned my tmap sensor with some carb cleaner. Still has problem.

I hadn't done anything to the car when this issue started for probably 3000 miles. The day before this started, i did add 1 qt of oil, which was slightly over full on dipstick.

About my car: 05 mcs 120k miles. 15% pulley, rmw cam, jcw intake, rmw header. Rmw remote tune, 212 whp. Only issue with my car is occasionally i get a po420 code from my high flow cat not being efficient. I am located in chicago area, Where are you?
Mike

 

I am near Austin TX. I originally wondered if it may be a weather related issue as around the same time the temp dropped into the 30's but it has been up to the 70's again and same issue so do not think it can be related. But what you describe sounds like the same issue. My engine light is staying solid, then after driving in neighborhood stop and go traffic, my DSC light comes on, then in about 5-10 seconds my engine light will flash and the car goes into a limp mode. If I restart the car it is fine and if I do not continue to stop and go the DSC light stays off and the engine light does not flash and the car runs perfect, I have driven down the highway 30+ miles at 70+ or down backroads at slower speeds. The car will idle perfect and the only time the DSC will come on and the engine light flash is stopping and going. I tested the wheel sensor theory while the car was at idle I disconnected the sensor and the DSC and then the engine light flashed within about 20 secs, this is the only time I have had it happen while at idle. I didn't think the DSC could put the car into a limp mode and most people on here said it does not either, but I think that may be based on the reasoning that in the owners manual it states that if the DSC is deactivated you will not have power loss, it does not state that if the DSC system is faulty. So to verify this I called two different Mini dealers service departments and described what was happening and the order of the lights. They both said it sounded like a wheel speed sensor but would need to diagnose as may be another DSC related issue. I specifically asked both techs if it can put the car into a limp mode and they both said yes. I called Mini of Austin and the Mini dealer in Orlando Florida (I called them because it was early in the morning and they are on Eastern Time so they were open, I wanted a different dealer to advise). I'm not sure if this is the issue and haven't had time to do anything else to the car but I think either I am going to get it plugged in or buy a speed sensor and try it(probably alot cheaper). If I go the trial way I am going to buy one front, and swap it from each side if the first side doesn't do the trick. The issue started after changing the belt which I pulled the passenger tire off, so I am going to start on that side. But, about 2,000 miles ago I put a new hub on the driver side, so I will go to that side if not. I did pull both sensors out and wiped them down and re-installed, but this made no difference, they had some build up but nothing crazy. Well good luck and if you do solve your issue please post it and I will do the same. Thanks

 

Update. I have put about 1000 miles on my car with no CEL. I never did find anything obviously wrong with the car. In the process of troubleshooting i checked all the plugs and torqued them , checked wires, coil. Cleaned tmap sensor with carb cleaner. Added a bottle of techron fuel injector cleaner, Removed and cleaned off front wheel speed sensors was the last thing i did. No problems now.

 

I broke down and decided to bring the car to Mini for diagnostics. So a $117 diagnostic fee to find the issue but worth not chasing anymore. The crankshaft pulley rubber is separating and causing the crankshaft sensor to read a default. This triggers the engine light and DSC putting the car into a limp mode. The P0300 code is generic according to mini and could be many different items, but the issue was not a random misfire as I thought before (but that doesn't mean it might not be for other people). Hope this helps someone else

 

What's next?AST super damper??

 

You are lucky in that your failure was not as sudden as most people find it simply flies apart taking something else with it! You have a number of options for either cheap or quality replacements: http://new.minimania.com/MINI_Cooper_Harmonic_Balancer

 

So I made the repair and 1,000 miles later no issues. Right when I put the new balancer on the car was fixed.

The repair was fairly easy, I did it myself with a floor jack and hand tools only in about 2 hours. With a lift, a helper, and air tools could be done in less than an hour. When I pulled the old one off it was seperating and was obvious the issue, but this could only be seen from the back side, on the front facing out it looked fine, so without pulling or Mini reading the code you would not be able to see the issue and since it was not making any noise I did not suspect it. So hope this helps someone else in the future.