I was changing the oil today in my '04 MCS and decided to do the HAI modification also since I had the parts. I put everything back together and start the car, it idles low and rough. I tried to rev it up a bit with no success and then shut the car off.

Looking under the hood, I saw that the plug from the throttle body was unplugged still, so I plug it back in and go to start the car again. Everything seemed fine so I went for a drive. Once I hit the main road I give it "a bit" of gas and then let off. I'm now in limp mode, with the SES EML DSC TPMS lights on.

I make it home and cycle the ignition a few times and the lights turn off. The car idles fine, and revs fine with no load. As soon as I try to drive it though, the same thing happens.

The boot on the right side of the intercooler looked to have moved a bit, so I retightened it and checked the vac lines for leaks. I then had someone rev the car and the bypass valve does not seem to be stuck, as the plunger operates fine.

I did have some intermittent rought idling for the last 6k miles or so (car now has 52k) that would correct itself once I gave it a rev or two. Could the rough idling be caused by bad plugs? I'm assuming the car ran pretty rich with the TB disconnected, so would that put the plugs over the top? I wouldn't think that the TB would just die when I ran the car with the plug disconnected.

I will be getting a scan tool and some new plugs tomorrow, but I just wanted to see if anyone had any other ideas as I kinda need to get it running again by sunday...

Thanks for any help/advice anyone can give.

 

ok, so I scanned the codes and all I have is p0642. Sensor a reference voltage circuit low. Anyone have a clue as to what this means? It's not too specific.

I've cleared the code and it comes back as soon as the car is turned on.

 

Check this out....
http://www.mini2.com/forum/faults-fi...ult-codes.html

 

One more thing unhook the battery for a while and see what happens.

 

thanks for the reply, unfortunatly, that thread has the same thing for that code. Nothing specific though, I did read that it may be the knock sensor but I'm not sure and Ive been doing all this from my cell phone!

 

make sure the TB connector is really, really seated. I'd had a time when I thought it was on but it wasn't connecting well. there are two potentiometers in the throttle body to check it's position (for redundancy and safety) and if the readout on those is wonky you'll get codes. Really press it down. On mine, it was locked and still had issues.

Some rough idles isn't too bad as the car learns a bit. But if it won't go away, thats a sign of a bit of a vacuum leak that isn't constant.

Also, idle issues can come from T-MAP sensors problems. Make sure the connector is in good shape and well seated too.

Good luck!

Matt

 

I disconnected and reseated the plug. Still nothing. Althogh disconnecting the plug gave two other codes (p0123 & p0222) which where cleared with no further problems.

 

Did you read Post #4?

 

Yeah, I did. I tried that a number of times trying to reset the ecu. It was even disconnected overnight. Once I turn the car on, the code comes right back.


It will be going to the dealer on Friday, but don't let that stop anyone from giving advice, I would prefer to take of this on my own.

 

So after looking at some wiring diagrams, I found the plug for the knock sensor. Everywhere I looked, that generic code is for the knock sensor. I unpluged the connector and nothing changed.

Will the car normally get a code with the knock sensor disconnected?

Also, does anyone know if lack of knock sensor will put the car in limp mode?

Thanks again!

 

I did some more checking for that code here is more info.
http://wiki.ross-tech.com/index.php/17026/P0642/001602

 

Thanks for the link!

It looks like that code is part of the symptoms for a ECU reflash on the VW/Audi 2.0TFSI engines though.

Although I did get a better description of that code from the VW forums after looking at that link.

"Knock Control Control Module" I unpluged the knock sensor and drove around in limp mode for a few miles and I got P0326 for the knock sensor, pluged it back in and the code cleared, so it's not the sensor.

I also checked to see if the wires were shorting or otherwise messed up and there doesn't seem to be any problems from the knock sensor plug to the ECU.

I would guess that the knock sensor control module is part of the ECU, correct?

Still waiting on my Bently Manual...

Does anyone have the voltage specs for the knock sensor? I was getting 2.5 volts, but I'm not sure if that is within spec.

Could just the knock sensor portion of the ECU have gone bad?

 

Did you resolve this issue? I have the same code showing on my 03 Cooper S. It happens a couple times a week. Turning the car off and back on will cause all lights except for the SES to go off. This also causes it to go out of limp mode and it drives a normal. It seems to randomly happen. I've had this happen for a few months now. Initially it was once every several weeks. For the past couple months it has been more frequent, about twice a week.

Thanks

 

I had this happen this summer on a vacation to Colorado. Before I had Tillie towed to Denver, I pulled the DSC and a few other fuses. Put em back in and haven't had a problem since. I'm not sure if this was recommended but somewhere I found this suggestion on the web and it worked.

 

My '05 MCS does just about the same as what has been stated here. Seems to be an epidemic with MINIs now for some reason. Most people are blaming the BPV. I dunno, I'll change mine and see what happens. Looks like a design flaw from the factory. The dealer should have the fix the little lovelys for free.

 

I had the same problem with the SES light on my 05 MCS. on, off, on, off. The dealer told me it was the fuel i was using "to much ethenol". They told me to go to a lower octane rating and see if it persited, it did. I have an Alta CIA, I noticed the light was more frequent when I cleaned an oiled the filter. I switched the filter to a K&N Cone filter and haven't had the light since, Don't know if this helps, might have something to do with the fuel/air mix