My sisters mini cooper s clubman was driving down the road and just cuts off. That's where the problems started. I looked up online and thought it may be a hpfp. After replacing the hpfp I noticed that I wasnt getting fuel from the Lpfp after installing a new lpfp I still am not getting any fuel.
started to diagnose the wiring. White wire with blue stripe carries power to the fuel pump. Test it with oms it's fine. Test the fuel pump fuse. It has 12v test the white blue wire where it would have plugged into the Junction/fuse box (jbe) it only has 9 volts. All problems point to bad relay. But the relay is part of the fuse box soldered into the computer board. So I take apart the box. It's a double stacked design. I cut the little studs that hold the two computer boards together and split them into two pieces. The fuel pump relay solder is hidden under there. Upon closer examination I seen that the solder around one of the points on that relay was cracked. Such a simple problem that took me 3 days to find. So I soldered the point and then soldered together the 2 boards via the studs that I had cut in half installed it into the car and it starts right up! Something as simple as a crack in the solder can cause such a huge problem and cause the whole junction box to be replaced. It's a $250 used. Just wanted the internet to know how to diagnose such an issue and how to fix it. Also this could be caused by a bad fuel pump relay which can also be soldered out and replaced for $13 w/shipping.

Its located in the passenger side footwell. Jbe fuse box junction box. 2 10mm nuts hold it on the lower left and right corners. Unhook the battery negative first. Then unhook all your connectors they only fit into there proper places so you wont plug them in improperly . The main 12 volt red power wire just pulls out. Nothing special. Just Took me a little to figure that out .

Take a photo of all your fuses. Take them all out, remove the back of the back of the jbe with buy carefully prying it with a knife.

Out side of the plastic box it will look like this. I used wire cutters to cut the studs to split the 2 boards apart. Here is a later photo they have been soldered back together. I just soldered the seam that I cut.

This is the problem.. This was between the two boards where the fuel pump relay is soldered into. The fuel pump relay is the Nec philippines ep2f-b3g1st. If yours is bad just order one online by using that number. They are $4 shipping is around $8.

 

Greetings from Aus,

Firstly my sincere thanks for posting this article. I've been chasing a fault with a friend's Cooper S for a while and after much testing and googling found your article. Had almost the exact symptoms - The pump worked when powered externally, there was 10.7V at the pump plug when cranking (disconnected), BUT 0v when back-probing the plug connected to the pump. So, having concluded the controlling relay was the culprit went looking. There are a range of opinions out there as to where it is located (not it's not in the engine bay). After removing the fuse box, which isn't that hard really, I disassembled the housing and tentatively snipped all the board link pins (all 30 of them). Examining the Relay pins, I found this


Which I thought was remarkably like yours.

The problem joint was reflowed and the link pins carefully cleaned, tinned and rejoined. Note - You'll need an iron with a bit of grunt as some of the pins are connected to tracks that really draw the heat away. I used an 80W iron, did the trick.

All back together, and as soon as the battery was reconnected the pump did its brief prime run! Success. The Mini lives again.

Thanks again for taking the time to post this article - not sure I'd have had the confidence to delve quite that deep without it.

Cheers

 

Hi I'm glad it helped you out. My own thoughts about why this occurs is if one has a weak battery and prolongly jump starts the car with a booster; because the fuel pump is on the ignition circuit the high amperage booster box heats up and eventually melts the relay solder joints. I don't know if your buddies car is the direct injection engine, but on my sister's mini s clubman I had to replace the hipressure fuel pump from ecs tuning. You can check the hi pressure fuel pump pressure with a scan tool, it should be around 3,000 psi. Don't quote me on that I did this job a few years ago now.
I'm glad I was able to help and want to wish you luck on your mini Cooper.

 

Hi all, new here but came across this thread when looking to solve a similar issue. My 2011 R56 hatchback S was starting to have an issue where it would suddenly lose fuel pressure and stall out (as if running out of gas). It usually does it around 30 mins after refueling. After taking to the dealer to have them diagnose they said it was either the LPFP, the JBE, or both. I'm good at soldering so I pulled the JBE off today and it's IDENTICAL to both of yours, with a cracked joint in the same place and a scorch mark around it. I made the repair as you laid out and am going to test to see if that solved the problem.

My symptoms were identical to either of yours as mine would start up, but it was getting harder and harder to start up after it happened. Time will tell and ill update here if my issue stops.

 

Glad I was able to help!

 

hello,
I need some help my board looked the same however after re-soldering now the car won’t start, I can’t lock or unlock the doors, no headlights or wipers has anyone had this issue before?

 

sorry I usually don't monitor this thread anymore. I would check the fuses and wire pins, as maybe something simple went wrong during assembly/installation. I didnt have any issues like that after replacing my JBE. let me know how it goes with figuring it out. you can check the paths of the board with an ohms tester to find what is wrong. also post a pic of your board.

 

I end up having to change the fuse box entirely to fix my issue.

 

I would like to thank Samkarpets, madkene and mini_fractal for this thread. I had same problem with 2008 R56 Cooper S and found this thread by searching. Symptoms were occasional engine cutting out, no rhyme nor reason, and no fault codes showing up. This thread with pics and description gave me the confidence to go for it. I made some videos to help others like us in the future. They are bit boring but will hopefully help others; I put them into 4 as a playlist to separate them into chunks. (can't link to the playlist so I put the first video below you can find the following ones from there)

I bought a new NEC Relay EP2F-B3G1ST relay from aliexpress for £6.90, only place I could find it for sale. The pic of my dry joint is below, same as everyone else. Anyway, it was successful and mini has no fault codes caused by me, and is running fine.

 

I have same problem, I took the fuse box out,split it but found no solder joints that looked bad. I soldered all the pins back together, Now i'm still with no power to the pump.Any suggestions?