Hey guys. I have an 04 MCS with 58,000 miles. About a week ago I got a SES light. I had the code pulled and it was P0507. Basically the code is for an unexpected high idle. It said either the iac (idle air control) was faulty, dirty throttle body, or vacuum leak. Correct me if I'm wrong, but the r53 doesn't have an iac valve because it uses an electronic throttle body. So, first thing I did was take off the intake and remove the throttle body. It had a little build up, but pretty clean. I went ahead and cleaned it really well. I checked the butterfly flap and it seemed to open and close fine. Put it all back together and it idled perfect. Next day.. Started throwing the same code. It was on and off though. Sometimes it would idle fine, then high and the SES would come on again. So, then I started checking for a vacuum leak. With the car running I sprayed starting fluid on the vacuum lines, around the throttle body, valve cover and everywhere I could think of that might be leaking and nothing. I tried blowing smoke through the vacuum lines with the car off to see if I could see a leak.. Nothing. I took the intercooler off, cleaned it and checked for cracks. Looked fine. Checked the rubber boots, no cracks or holes. Unless its small and I'm having trouble finding it, I don't think I have a vacuum leak. Also, if it were a vacuum leak I would think it would be constant? Sometimes it idles fine, then high. So, I'm kind of at a stand still. I thought maybe it could be the tps (throttle position sensor)? I think it's all one unit with the throttle body, so maybe the throttle body needs to be replaced? Any input, suggestions or corrections on anything I've said would be much appreciated.

 

My thoughts as well reading this based on code/production year and symptoms...

The electronics to the TB are piggy backed right onto the housing and not avail separately.

Bet you can find one on ebay.....but get new gasket if you end up going this route.

13541503358 THROTTLE HOUSING ASSY2.38 1 $304.3302 13547509045 GASKET, THROTTLE BODY0.03 1 $9.05

 

Thanks for the info. Would It be worth upgrading the throttle body? I'd love to improve the throttle response.