I did some searching here and couldn't find my problem, so I'm starting a new thread...

The car:
A 2006 MCS - Manual - almost 12,000 miles
I've kept my fingers out of the engine bay... it only has an Alta foam air filter (the drop-in panel filter). Everything else is stock in the engine bay. I've done lots of cosmetic mods, upgraded brake pads / fluid and added a rear sway/front brace.

The problem:
I was driving along at 45 MPH on a highway and I downshift from 5th to 4th. The SES light blinks 4 times and then stays on. The DSC light comes on and refuses to go off with the switch. The car loses about 75% of it's power and I limp off of the highway and into a parking lot. The engine is still running, so I pop the bonnet and listen. It sounds like it is running on 3 cylinders. It's almost like the DSC kicked in but never turned off.

I turn off the car and re-start it. Everything returns to normal, except the SES light is now on and won't go away. I restart the car 5-6 times and it runs fine. I cut a quick, hard turn in the parking lot and the DSC kicks in for a second or two and then returns the car to normal... just as it should. I finish the drive out to lunch and return to the office w/ no problem.

The scenario:
I've got a service appointment next Monday for the first free oil-change.

Any thoughts???

 

Supercharger Bypass Valve.
Sounds like the same thing that happened to me about 6 months or so ago.
I was cruising along and traffic in front of me openned up so I put down some power only to have it all disapear.

 

I just got off of the phone w/ the SA (one of the better ones, by reputation).

He suggested that it might be the bypass valve as well... He figures that it got stuck in the open position on the downshift and that took all the power. It was probably running rough as it wasn't getting the air computer expected it to be receiving.

I'm going to hang on to the car until the scheduled service next Monday (1 week) for now. If it keeps happening, I'll call 'em back. If I can hold out for the scheduled service, I get a loaner...

 

After stopping/restarting the car in the parking lot 5-6 times, driving to lunch, back to work, and home last night, the SES light is no longer on...

 

I would still suggest you take it in and have it looked at. Last thing you want is for the bypass valve to get stuck open again and an inoportune moment.

 

It's definately going in. I'm driving very carefully for the next few days... It takes a while to set up a loaner at my dealership and I'm holding out for the valet service to pick up Jango at my office and leave me another car to drive until they can figure it out.

If it is a bypass valve, would a catch-can help? What is the fix?

 

The fix on mine was replacement of the Bypass Valve assembly. Wagnbat went to another dealer in the area and I think they fixed his by shaving the valve down a bit so it wouldn't get stuck again.

Something like an OCC (Oil Catch Can) wouldn't have an effect. The problem that is happening is the valve is getting stuck on the side wall of the assembly.

 

This is the exact thing that happens on my 2006 MCS. I took it in to the San Antonio dealer and they had zero clue. The computer was showing a misfire but they found diddly.

In the end I had no choice but to take the car back.

I guess once I hit my first oil change, I'll suggest the above solution to him and ask about getting it replaced.

The SES problem has diminished for me. It used to happen once every week and a half-ish...pull off...turn off engine, restart and everything's fine. Really frustrating for a new car. Currently it hasn't happened for nearly 2 months.

 

Well, I just got the loaner (BMW 325i - nice car - the fit and finish feels very familiar) and Jango is off to the shop. Hopefully I'll have something to report soon.

 

Well, their full day w/ the car just came and went... no news. Thank goodness I got a loaner! I miss Jango, but at least I've got something that's a tad bit fun to drive. It's actually a very comfortable car w/ a nice, tight feel to it.

 

The OBC sent a "misfire code", according to the Service Advisor. They ran several tests (what tests, I don't know) and said that the engine was running just fine.

The SA said that he had seen this problem at least once before (gave me the screen name of a local club member who had the exact same problem) and it never came back.

Oh well!

The valet is bringing the car back to me right now. If they give me paperwork with the code and any additional information, I'll post it here.

 

I got the work order back w/ the car. Here's the section about this problem:

*CK ENGINE LIGHT HOURS: 0.25
CUSTOMER REPORTS - SERVICE ENGINE SOON LIGHT IS ILLUMINATED AND VEH WILL STALL OUT AND NOT ACCEL OVER 10 MPH. CHECKED FAULT MEMORY. FOUND FAULT CODE P0300 STORED. RAN SMOOTH-RUNNING / MISFIRE TEST MODULE. CAR PASSED SMOOTH-RUNNING/MISFIRE TEST MODULE. CLEARED FAULT MEMORY.

 

Ah, yes ... the dreaded P0300. Our MCSC's back in the shop for the 4th time with this one. Generally happens to us at low speed, so I'm fairly certain they've ruled out the sticky bypass valve. The SES light starts blinking, the DSC light comes on steady, and the car goes into limp mode. Pull off the road, turn off car, wait, restart, and the engine runs fine ... for a couple of miles, at which point the scenario repeats. By the time we can get it to the dealer, it's running fine, and they can't repro. Computer stores only the random misfire code, so they're not getting anything useful for diagnostic purposes. The bad news is, it's REALLY sporadic - only happens every few months. The good news is, the period over which the behavior is repeating has seemed to lengthen each time. (This time, it happened 4 days in a row) So, we haven't yet managed to get it to the dealer for a repro before it returns to normal, but there's hope for the future. They've run a ton of tests on our car, but haven't found a solution yet. They're doing everything they can to repair it, considering they're pretty much in the dark as to the cause - the last attempt was a valve job. Haven't heard yet definitively on a fix this time, but it sounds like they're considering replacing the flywheel.
I've found a couple of other individuals experiencing what sounds like the same problem, one of them gave up and sold the car, the other one is living with it.
Sorry for the loooooooong post, but I'm hoping to be of some help to others with this issue, or even better, that someone out there may have an answer for the rest of us.

 

I can't believe how exactly the same my problem is to the one posted by Roymo. Mine used to happen once a week...sometimes a couple days in a row. Now it's spreading out to month+ spans of time. I haven't had it for nearly 2 months now. Not that I should happy that my brand new car has gone 2 months w/o problem.

Please keep this thread alive w/ insights. My dealer went through all the same steps, got the same misfire readings and was unable to reproduce.

 

If your having a misfire, its mostly due to bad gas. As for the cel and dsc light stayin on....thats a problem with the steering angle sensor which needs to be either replaced or recalibrated. had pleanty of these issues in the past few weeks and all we had to do is swap cylinder 1 to 4 plug and hope for the best....no problems after that ive seen since this was done. your cel will go off with a few cycles of the key but the fault is still stored. theres a bulletin out about the new gas being seen all over with alcohol additive instead of MTBE. bmws are havng the same issues as well

http://www.lubedev.com/articles/alcohol.htm

 

1FSTMINI -

This is exactly what my dealer told me last week when I had the same thing happen. Seems some of the stations locally are cutting the gas to get more or jack up the octane rating. Variety, not a pattern to it.

Corn is to eat, not run in my engine. (IMHO)

 

I havent had any issues with my own car so im thinkin that most modded engines will be fine with the alcohol additive than stock ones.

 

Purah,
FYI, our dealer did end up replacing the flywheel - theory seemed to be that a manufacturing flaw might have caused it to be out of balance. We're back in waiting mode to see if it recurs. Of course, this is a very generic error code, so there's no guarantee that our issues are caused by the same problem.

 

there was an issues with flywheels for most 05 cars. they have an updated flywheel to fix the problem....when i picked my car up in jun eof last year, i had the car for THREE HOURS and found out i had one of those bad flywheels cuz i heard a loud metal to metal noise which was the dual mass flywheel smacking each other

 

Well first I am glad not to be the only one but.......
Had the oil changed, brakes bled, control arms added and a single, yes that is right a single spark plug changed yesterday and the same problem is occuring to me today.

On quick acceleration it stumbles and feels as if it is flooding. The single spark plug change was because previously the aluminum head coughed up one of the plugs but when the dealer retapped the hole they replaced the plug with a stock unit not a denso. So in goes the Denso and the problems started as soon as I drove away from the shop. I assumed the spark plug change might have cause a little trouble initially but it never did when they were mismatched.

 

Well, we have an early '06 production (took possession in November), and there were no noises or other suggestions that there was a problem with the flywheel. No clutch issues. We did a bit better than you - had the car about 26 hours before it went into limp mode with the first misfire.

 

Sorry guys.....I read the bulletin wrong....Alcohol and MTBE is ok but its the Ethanol there starting to use which is the issue....Not all gas stations are using ethanol from what ive seen so yoyr ok for now unless they all switch over

http://www.toptiergas.com/

 

In Texas, they have all transitioned over to up to 10% Ethanol. I'm hoping it's just a 'summer gas' thing, but I think it's here to stay.

I've heard issues w/ the addition of ethanol and fuel pump / delivery systems. The Ethanol is my hydroscopic (water loving) than MBTE additive... this is causing the fuel to pick up more water by volume and is soluabilizing the crud (and water) in the bottom of fuel storage tanks at the stations. This is turning up in people's gas tanks and clogging fuel pumps, etc. I've heard that it's a problem in BMWs and MINIs, both.

 

Went into limp mode. 2000rpm max engine speed. Restarted and it seemed OK, but I had it flatbedded to the dealer today. Time for first service anyway. [2005 MCS with 10200miles]

 

P1688 = Electronic Throttle Control Monitor Level 2/3 Mass Air Flow Calculation