R53 limp mode
 

A few weeks ago my 05 r53 went into limp mode. Check engine light, traction control and emissions light all went on. Revving the car past 2500 rpm causes the car into limp mode. Replaced the map sensor cleaned the throttle body to see if that would work. No luck with that. Anyone know more about this issue before I take it into my local shop? Thanks in advance!

Had a similar problem - under full throttle acceleration, the car would go into limp mode around 5000 - 5500 RPMs. Turning the car off would usually get me out of limp mode, and going easy on the throttle would keep me out of it. Turned out to be a failing belt tensioner letting the belt slip under high load. Should be easy to check if you have the belt removal tool.

Check the operation of the speed sensors too. If those fail, the dashboard lights up like a Christmas Tree, and sometimes forces limp mode.

Have you pulled codes?

i don’t have the belt removal tool. What exactly should I be looking for?

I haven’t had the opportunity to pull codes. My code reader doesn’t work for minis. I’ve been on the look out for one.

Most of your autopart stores will read the codes for free as it is a means to generate some parts sales in certain instances.

If you can get the belt off, work the tensioner by hand and see if it returns fully to its original position. (I had to give mine an assist for the about the final half-inch of its travel). Replaced it and the problem went away.

Best price I found on the tool was $35 (incl. shipping) on amazon. It's still there ("EWK serpentine belt tool kit supercharged for BMW mini cooper/S...." etc). I leave it in the trunk with a spare belt.

If you smell burning rubber check the crank pulley. They are so prone to failure they are the most common failure to cause limp mode. If so go with a new ATI damper and you won't have to worry about it happening again.
https://www.waymotorworks.com/super-...ulley-r53.html

I had an almost identical problem on my 2007 R52 recently. Traction Control, check engine, emissions indicators plus limp mode. Occasionally all the dials would go off the chart as well. Took it to a specialist auto-electrician. Took a couple of days to trace but turned out to be the tachometer triggering a whole bunch of codes and messing with the body controller - sending the trans into limp mode. Replaced the tachometer and everything was back to normal.

Okay so I went out and bought a code reader. It threw three codes which are the following.
https://cimg7.ibsrv.net/gimg/www.nor...3389c86a30.png
https://cimg9.ibsrv.net/gimg/www.nor...64546f4230.png
https://cimg8.ibsrv.net/gimg/www.nor...86ab33342f.png
https://cimg3.ibsrv.net/gimg/www.nor...91dfd7107.jpeg
https://cimg5.ibsrv.net/gimg/www.nor...c9b6773b9c.png

Those are generic, but I would lean toward the throttle body being bad
https://www.waymotorworks.com/thrott...-cooper-s.html

when I remove it to clean it I tested it out. The rubber seal was also replaced the same time. I would let the car reach operating temperature then rev the car to 2500-3500 rpm. With the throttle body visible the doors worked fine. Reved it a few more times then the doors would open about quarter way. Is there a way to diagnose if the throttle body is bad?

It's hard to test as usually it's just one of the sensors in it that fails and causes it to go into limp mode as it can't be correctly controlled by the ECU when the sensor sends the wrong signal.

I did replace the throttle body over the weekend! Unfortunately it did not resolve my issue. I think I’ve reached the point of just taking it to a shop to get it sorted out.

It says "Pedal Position Sensor"; did you take a look at the pedal itself?

I did not check. It has since been dropped off.
https://cimg7.ibsrv.net/gimg/www.nor...81399f19d.jpeg

Keep us posted please.

Another vote for the Crank Pulley. Mine did the same thing. Look below the crank pulley for rubber dust and check for burning rubber smell.

did you eventually find the problem? my car is doing the same thing as well...

So after few months with no update I’m here with sad news. The car was fixed after a week or two after dropping it off. The issue like many forum users said was indeed the crank pulley. So I opted to install a 17% pulley along with corresponding parts. Unfortunately after two days of the car being returned a relative of Bambi decided to play hit and run. The vehicle was totaled out by insurance but since have bought the car back! Parts have been orders and are weeks away. Unfortunately here in Michigan weather isn’t great so looks like it’ll have to wait. Sorry for a long overdue update. Thanks for everyone who responded with some feed back.
https://cimg1.ibsrv.net/gimg/www.nor...5e0cd2452.jpeg
https://cimg4.ibsrv.net/gimg/www.nor...8e815c1fd.jpeg
https://cimg5.ibsrv.net/gimg/www.nor...ac9458d4f.jpeg