Hey everyone, I'm new to the forum, but I was hoping you guys could help me figure out what's wrong with my 2004 r53.

Here are the symptoms:

My check engine light is on, and the trouble code reads Idle Air Controller
With the A/C button turned off, Idle fluctuates between 1000 and 2000 rpm
With A/C button turned on, idle slowly settles around 1100 rpm
Experience a loud click and car jerks suddenly whenever the throttle pedal is engaged and disengaged
Throttle response is delayed

I took it to a guy, and he said it might be a vacuum leak in the intake manifold, or that it might be a problem with the ECU and I might have to buy a replacement.

Do you guys have any ideas?

Thanks!

 

I doubt that it is an ECU problem.
Since the code is for the Idle Air Control, it could just be a small vacuum leak which makes it difficult for the computer to maintain a good idle. It could also be the Idle Air Controller.
Where is the loud click coming from? Is it coming from the gas pedal area or the engine compartment?

 

The loud click sounds like it's coming from the engine compartment. What do you think could cause the noise?

Since mini's don't have idle air valves, does the ECU just control the electronic throttle to maintain idle? Would the problem be somewhere in there?

 

First step...Take it to a different "guy". If he says you might need a new computer as soon as he sees it...RUN away! He is just gonna run up the bill, or he doesn't know jack....
The click is hard to diagnose....could be anything from a PCV valve, and engine mount....heck...anything...it may or may not be related....
Find a local "guy who knows MINI's...check the forums for a trust "guy" shop in your area.....

 

The idle is controlled by the ECU and the EDR (Electrotic Throttle) which is located on the throttle body. When a heavy load is sensed, such as the AC turning on, the idle is increased. The target idle speed is 750 RPM. If the voltage goes too low (about 11V) the idle speed is also increased. There are ways to check the EDR without just starting by replacing the ECU.

I suspect your idle problem is not the ECU but probably a vacuum leak.

 

It turns out that it was a leak in the intake, in a hose leading to the supercharger. Hopefully once replaced, it'll fix my idle problem. Thanks for your help guys.

 

Glad you figured it out!