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2002-2010 E53 x5 E60 E63 E64 E65 E66 Intermittent Crank Issue Solved

2002-2008 E53 x5 E60 E63 E64 E65 E66 Intermittent Crank Issue Solved

Part Number: 12.52 7 510 638


Carol called to tell me she was having starting problems with her 2008 750Li. We set up an appointment so that I could inspect it. The starting problem was intermittent and we couldn’t be replicated it on demand, so she decided to leave it with me. It took a couple of days before the no start problem happened again. I scanned the car to see if there was a fault was being registered. Nothing was coming up indicating everything in the car was ok. Since there was no fault to go by, the only thing that occurred to me was to find out what relay or module was responsible for operating the starter. At the moment, I regret that I could not figure it out. She picked up her BMW days later.

Several months had passed when I experienced the same issue with my personal 2005 750Li. I stumbled across a YouTube video that mentioned a module I’ve seen before but hadn’t made the connection with the problem. The module is called the Integrated Supply Module (ISM) located by the DME (Engine Computer). After opening it up I found out that it has a series of relays that operate the starter. Curious to see if one of the relays was the problem, I started removing the casings looking for signs of wear. I found that one of the middle relays had darker contact points with carbon build-up. If these relays were serviceable, I could’ve taken the relay out to clean it. But since it’s not, I decided to buy another module and see if it would fix my car.

I knew that this part was just a simple module made of relays and resistors that would require no coding or programming at all, regardless of what BMW would say. So I called them up to order the part. That same day I replaced it in my car and solved the mysterious starting problem completely.

The same customer happened to call me again, asking me if I had learned anything knew before she took it to BMW to get it fixed. She had been quoted $1,500 between diagnosis, parts, installation, and programming. I told her that I had just experienced this exact same issue with my personal car and told her to bring it in. We replaced it the next day and I’m happy to report her BMW has also been fixed saving her a total of $1,220 she can take to the bank.


Does your BMW have trouble starting let alone cranking at times ? Does it click at first, but not turn over and start? Does it randomly shut off while driving?

I have even seen sluggish performance under 4k RPM and the occasional P R N D Lights Flash which will cause your car not to crank as well.


 If so, your Integrated Supply Module (ISM) may be the problem. As these BMW’s continue to get older, this issue is becoming more and more common. It might even get to the point where the car doesn’t even start at all. Below you’ll find pictures to help you locate and replace it the part yourself. You can purchase this module directly from us by clicking here or on the image below. You can also call me if you have any questions or concerns. Tomas at (951) 522-4032


X5 E53 4.4i 4.8i 2004-2006

5 Series E60 E61 545i 550i M5 2004-2010

6 Series E63 E64 645ci 650i M6 2004-2010

7 Series E65 E66 745i 745li 750i 750li 760i 760li Alpina B7 2002-2008




Check underneath the passenger cabin filter.


Lift the plastic cover.


This is where the ISM is located.


Start unplugging and remove the old ISM.


Insert the new ISM module.

Make sure all plugs are connected properly.


Secure ISM in its proper location.


Installation is Complete.