Hey guys! So my gf has a 2009 R56 Base N12, but it has the same JBE as a lot (not all) of other R56’s.

And you guessed it, it’s the one that’s prone to the fuel pump relay failing. Or, more specifically, they seem to run so hot that they break the solder joints on the circuit board over time. And you can actually just desolder and add new solder sometimes and fix the issue. But I’m not the type to go that deep into a job and not fully replace an item that may or may not fail again in the future. If I’m in there and it’s possible, or likely, to fail again, I’ll just replace it.

Also, I know that there are legit places that will replace or fix this for you for $200ish. But again, in my opinion this is a clear design flaw. They get so hot that they heat score the circuit boards where they rest. Not to mention that you have to remove the JBE, open the plastic case, desolder 2 boards from each other or cut them apart and resolder after, just to get to the relay. Then desolder the 8 pins. And oh yeah, the only place that I can find the factory relay from is China, then wait a month ish to get it.

ALL of that sounds completely horrible! So instead, I used my 22 years of submarine electronics training and experience and found wiring and pin out diagrams instead to try to figure out how to fix this easier and make it better, more reliable, and more accessible. Not to mention that it HAS to be helpful for the life of the rest of that circuit board to remove that heat source altogether if possible.

I figured that someone else HAD to have already reverse engineered this thing and done the same. But if so I couldn’t find it on here or the internet in any other place. There is one thread from about a year ago where a guy ALMOST cracked the code and got it right, but not quite.

So now that I gave all of that background and story, my next post will be what my plan is. The relay that I ordered won’t be here until tomorrow. So I’ll post pics and results when I get and install it. But I’m pretty confident with my idea.

 

So we really only need to know a few things to make this work. Specifically, only 4 wires.

1. Like all automotive relays, it needs a constant 12v.
2. Key on power. Since you clearly only want your fuel running at that point.
3. A DME trigger, as that also is a trigger for the K96 relay to activate. In this case, that trigger isn’t a power source, it actually is a ground. So the circuit is grounded by that DME wire and doesn’t receive actual power.
4. The wire that actually feeds power to the fuel pump in my case, or LPFP for you guys with an S.

Now, because we’re moving this off of the circuit board and it applicable fuse panel, we need a fuse as well so that wires don’t melt and electrical fires don’t start in the event of a casualty or short. In my case, the factory fuel pump fuse for N12’s is a 20 amp.

So I ordered a 4 wire fused relay. They are super cheap on Amazon and I ordered mine last night and it will be here tomorrow. Mine comes with a 30 amp fuse, but again, I’ll be dropping it down to a 20 amp.

Access to all of the wires needed are VERY easily accessible right at the DME area once you remove the passenger side kick panel covering. And that only requires a T-50 torx bit for the lower seat belt bolt and then it snaps right out.

So here are the 2 connectors that you need to disconnect to get the fuel pump wire and DME grounding wire. Each connector has one of the 2 required wires.

The black plug/connector has the DME ground wire. It’s purple/green. Which for non electrical guys, that means the wire itself is purple, and it has a green stripe on it.

The white plug has the white/blue wire that actually goes to the fuel pump itself providing power.

12v constant comes from the pink/green wire which needs to be spliced.

12v key on comes from the larger gauge pink/blue wire and also needs to be spliced.

The 12v power wire as well as the 12v only with key on are both also easily accessible in a wire loom near the JBE closest to the rear of the car. However, these 2 wires perform other functions as well, so they need to be spliced, as opposed to cut and wired directly to the new fused relay, like the DME and fuel pump wires.

DISCONNECT YOUR BATTERY BEFORE CUTTING OR SPLICING ANY WIRES!!!! Start with the constant 12v power wire otherwise, and it will remind you to do so and it will be a self correcting problem! Lol

Before you cut the wires from the plug, it’s good practice to leave enough wire on the back of the plug in case, for whatever reason, you wanted to easily be able to wire it back the factory way. And if you cut too closely there won’t be enough slack left to do that.

Relay Wiring.

Pin 30, usually the red or sometimes yellow wire on the relay harness depending on the brand of relay you order, connects to the 12v constant pink/green wire splice.

Pin 86, the white relay wire, connects to the 12v key on pink/blue wire splice.

Pin 87, the blue relay wire, connects to the fuel pump white blue wire that you cut from the white connector plug.

Pin 85, the black relay wire, connects to the DME wire that you cut from the black connector plug.

That’s it. Then make sure that you have the appropriately sized fuse and tuck it away next to the DME when you put your interior panel back on.

The whole JBE.

The black connector with the DME purple/green wire.

The white connector with the fuel pump white/blue wire.

A general 4 plug relay harness wiring layout.

Where the white and black plug/connectors are located.

The 12v constant pink/green wire and the 12v key/ignition on pink/blue wires that need to be spliced.

 

This fix and tutorial rocks! Thank you for posting your thorough and clear solution. I just implemented this on my wife's 2012 Cooper S convertible. I was daunted by the idea of ripping apart the circuit board to get to this relay, so your bypass solution was exactly what I needed.

 

A few questions. Where are the 12v constant and 12v key wires you are tapping into? Are they on the 2 plugs that you have to remove? I know noting about electrical so any help is appreciated.

 

The wires you need to splice into are down near the bottom of the wire harness at the rear edge of the fuse box. They do go into a plug on the fuse box (white, as I recall) at the bottom right. There is a big bunch of wires coming down the A-pillar at the back of the fuse box and two of those (colors as described in the original post) need to be tapped into, but don't cut the wires! Get yourself some T-taps (and spade connectors) or the basic blue wire splices (every auto parts store will have those). I prefer the T-tap solution because you can unplug the spade terminal if needed, but I ended up using the blue ones.

The wires you want to cut are on plugs at the forward edge of the fuse box and there you can go ahead cut the wires as described by the OP.

In doing this you are getting the 12V and 12V-key on signal from the wiring harness to power the relay, but you are essentially putting a new relay IN PARALLEL to the dead one on the fuse box circuit board. The fuel pump then only receives its power via the new, external relay since you've reconnected its blue/white power (goes to fuel pump) to that relay. The old relay just sits there without a complete output circuit.

If you are having a hard time finding the right wires, I can probably send some more pics, but not until end of the week...

 

Any body know if this is the same on a R55 1.6 petrol base model? That'd be grand ,cheers.

 

Hi all,
I have incorporated this modification as I have been chasing random stalling and failing to start - which has gotten worse recently. I have eliminated the ignition system as the cause.

Anyway - I find that this mod does not quite work as advertised - and it has taken me hours to get to the bottom of what is wrong (changing other components , doubting my work etc).

On my 2011 Cooper (1.6 petrol / non turbo) - the DME ground signal only goes to ground when the engine is running - not when it is cranking ! Therefore if you have lost the residual fuel pressure overnite - the car will not start. There does not seem to be a priming cycle for the fuel pump.

Has anybody else had this problem ? Is my DME faulty ? I'm guessing that the Cooper S will not show this problem because the HPFP will get the car started.

For now I have put a permanent ground to the relay and will install a LED light to monitor what the DME ground signal is doing.

Thanks all.

 

Does it not prime on unlock? The N18 cars prime on unlock (or maybe it's on door open... it's been a while since I've driven mine)

 

I too have this problem in my 2010 Cooper S. The HPFP does not get it started. I usually let have accessory on for a few second and then start the car.

To add more mystery to the story. My LPFP chews fuel lines for some reason. They keep breaking and I did find one that I think somehow melted. I changed the lines last time and the car started the first time with no priming for a couple of months. However, now I am back to acc on for a few seconds.

Why is it not priming? Also, anyone know what could be happening to my fuel lines?

 

Further investigation reveals it is even more bizarre. My permanent ground for the external relay did not fix the non start after incorporating the mod. I'm guessing the "ignition on live" doesnt actually go live until the engine has started. The only reliable way to start the car after residual fuel pressure has gone is :-

• Key in
• Do not press clutch
• Press start button twice to bring ignition on (i.e go beyond acc)
• Pressure clutch
• Press start button again.

However after all this the autostop start no longer works properly. If I come to a stop and the car decides to cut the engine ( as it should if the right conditions are met) - I get some message stating stop/start not working. At this point there is much cursing and frantic pressing of the start button and clutch.

I have to conclude that for my Mini this mod is not very good.

Completely fed up now. Been chasing this problem since November. Getting rid ( my son is taking the car off my hands). Would love a newer Cooper S - there is nothing else to compare to these go- karts. Dont know if I dare risk it - lost £4k in two years on this car.

 

Does anyone know if the DME and fuelpump wires really have to get cut? I have some posi-taps to splice into the wires, which should work great.

Also, i was wondering, with the bypass, will the pump still prime on Door-Open? Or only when the key is inserted?

Reason i'm asking these, is right now the relay on the board still seems to work intermittently. When it's cooler the relay may still get enough contact, and not when it warms up.

 

To be honest - I think I would only use this modification for troubleshooting. Once youve proved the relay in rhe FRM is faulty I would get it fixed. I've tried various combinations and all of them result in the car not working properly . I've had fuel activation fault code - i think this happens when you cut the dme wire. Stop/start doesn't work any more!

 

Do you have a link to the relay that you used?

 

So, I followed this and was running into the same issues as other guys above. I revisited a few other sites and saw that the same wires are used, but the ignition and constant wires were switched from where the OP put them on the relay. I switched mine around and the issue seems to have solved itself. Hopefully the issue stay remedied and this helps others out. Huge thank you to the OP for the info!