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Discussion Starter #1
So folks I need a little guidance.Over a week ago I turned the car on and after 10 seconds the car shut down, like it was running out of fuel.After checking the fuses, I found fuse 31,10Amperes,blown. I replaced it and it blew that one also.
At which point we disconnected the ABS module , since it was showing ABS and DSC lights on the dashboard.
Replaced the fuse for a 3rd time and the car started right away and performed with no issues.
We then connected the module again and blew the fuse.
At that point I disconnected the module and shipped it to get rebuilt.
After a week they called me and they told me that the module was in good shape and they would reimburse me for the service.
They informed me to check the wiring.
Does anyone know what I need to do here?... the harness,,, ??? Continuity from where to where?
Thanks in advance!.... and stay safe.
 

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Fuse 31 is also listed for the fuel pump relay, but I think that is for the non M models. You could double check your main pump fuse in the trunk.

Though from what you said the car dying like it was out of fuel, it could be the pump? What year is the car and the mileage? Has anything been done to the fuel system. I don't think a faulty ABS unit would cause the car to die though the wiser members feel free to correct me.

Check for any shorts of course and any possible damaged wiring.
 

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F31 supplies power to the fuel pump relay AND the ABS/DSC control unit. I'm guessing you have a bad relay or a short in the wiring to the relay.
 

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Discussion Starter #4
I will check for wiring. The fuel pump was replaced in April 2020, and the fuel filter was replaced in May of this year.
When the pump was replaced , the BMW mechanic told me that a critter had nibbled on the top wires of the pump... afterwards the car with new pump, no issues.

I had ordered a new relay and returned it thinking the ABS module would be the fix.
Now we need to see which ground or other component might be the culprit.
Thanks for helping me.k
 

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First thing to check is for a short. In the wires to things. Where fuse 31 plugs in one prong is 12V the other goes to the devices, with the key on find the 12v side. The other side is what you want. Key off both ABS and FP relay unplugged, check the path to ground with your volt meter. One probe in the other side of the fuse and the other probe on a solid ground there should be no reading other than what your meter said before which is usually 1.
It is going to be a hard problem to track down from the sounds of it unless you get lucky and that test shows something less than 1.
 

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You may know all this already- The ground is always the brown wire. There’s a few schematics posted on the forum - With the evidence of a rodent around the fuel pump I’d start the search there if you haven’t already and see if it got into the fuel pump wire harness... after that I’d start continuity testIng. Start at the fuse and work your way in.
 

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Not sure how a rodent gets under the back seat to chew on wires.....
You need to check out what the repair job looks like. It could be a really good solder fix and the problem is elsewhere, but could also be a sloppy repair with twist on connectors. Post pics.
 

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OP said
At which point we disconnected the ABS module , since it was showing ABS and DSC lights on the dashboard.
Replaced the fuse for a 3rd time and the car started right away and performed with no issues.
We then connected the module again and blew the fuse.
Wouldn't that indicate that there is no issue with the fuel pump/wiring, it is the wiring from the ABS module to the fusebox?

Regards,
Jerry
 

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Wouldn't that indicate that there is no issue with the fuel pump/wiring, it is the wiring from the ABS module to the fusebox?
It would be nice if it was as simple as that, but because there are several things on the 1 circuit, one of those items might be drawing too much, but not a heck of a lot more. Just enough to draw more in all the combined amps, more than the rating of the fuse. Unplugging any one thing may not remove the source of the problem, but still brings the total demand down below the fuse rating so it does not blow. These can be very difficult problems to resolve.
There are many different approaches to troubleshooting. After continuity is checked to make sure a wire does not have a small leak to ground, comes the fun and games. You can use a larger fuse to get an idea of how much extra is being drawn then keep reducing the fuse size until it blows, so 19 amp blows the fuse but 20 does not. If it is a 15 amp fuse you know you are 4 amps more than you should be.
Next you might disable the ABS and see what the circuit is drawing, then check the specs. Repeat the other way to test the ABS. Then it is just a bunch more rabbit holes. You usually end up having to isolate things unless you get lucky and something obvious appears, like a melted wire.
 

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Discussion Starter #11
It would be nice if it was as simple as that, but because there are several things on the 1 circuit, one of those items might be drawing too much, but not a heck of a lot more. Just enough to draw more in all the combined amps, more than the rating of the fuse. Unplugging any one thing may not remove the source of the problem, but still brings the total demand down below the fuse rating so it does not blow. These can be very difficult problems to resolve.
There are many different approaches to troubleshooting. After continuity is checked to make sure a wire does not have a small leak to ground, comes the fun and games. You can use a larger fuse to get an idea of how much extra is being drawn then keep reducing the fuse size until it blows, so 19 amp blows the fuse but 20 does not. If it is a 15 amp fuse you know you are 4 amps more than you should be.
Next you might disable the ABS and see what the circuit is drawing, then check the specs. Repeat the other way to test the ABS. Then it is just a bunch more rabbit holes. You usually end up having to isolate things unless you get lucky and something obvious appears, like a melted wire.
I will keep everyone posted on this thread. The module is arriving today and the new speed and pad sensors are arriving tomorrow.
So , I’m checking all the angles...I must say that I truly appreciate everyone’s help.
Keep the info coming... thanks
 

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The mechanic mentioned chewed wires, that is the smoking gun. Just pull up your back seat and have a look to start with.
 

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Discussion Starter #13
That’s where I need to check!. They conducted a pressure check at the dealership in April, we found the pump was leaking , the top wires had been nibbled on... it’s possible that the poor contact connection was not fixed properly... or the wire further down is causing the shut down... I will check under the seat... I hope that is the issue.🙏
 

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Discussion Starter #14
First thing to check is for a short. In the wires to things. Where fuse 31 plugs in one prong is 12V the other goes to the devices, with the key on find the 12v side. The other side is what you want. Key off both ABS and FP relay unplugged, check the path to ground with your volt meter. One probe in the other side of the fuse and the other probe on a solid ground there should be no reading other than what your meter said before which is usually 1.
It is going to be a hard problem to track down from the sounds of it unless you get lucky and that test shows something less than 1.
My question...?... if it shows 1, or less than one... what is determined?...no continuity?... not an electrical expert
 

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If it shows 1 then no continuity. With the fuse out that side is disconnected. With the ABS unit and the FP relay out or unplugged Then those wires should have no path to any where so no continuity. You want to look for two things, another thing on the circuit that the fuse panel notes don't mention (very common) or the wire has been chewed or rubbed and is touching ground or another positive wire, something. It is just the first step in ruling things out. It does not tell you much except if the reading is one then it strongly suggests that the wires are intact. That said another reason for high draw can be a half broken wire and if it is not touching ground it will still show 1.
Did you send the solenoids away with the unit or just the circuit box?
 

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the module only
Might be simpler than all that. I have notes on two cars I did and some notes from the forum when I was researching the first car I was trying to fix. The solenoid packs seem to short out with some common theme. You might want to have a go at them with an OHM meter and see if one section has a different ohm reading than the others.
 

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Discussion Starter #18
Might be simpler than all that. I have notes on two cars I did and some notes from the forum when I was researching the first car I was trying to fix. The solenoid packs seem to short out with some common theme. You might want to have a go at them with an OHM meter and see if one section has a different ohm reading than the others.
Sailor,,, I will keep you posted ,,, thanks for helping me. Keep the information flowing.
 

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Discussion Starter #19
Update!... Most recent work done to the car was replacing two power steering hoses which were leaking, that went smoothly. Two days ago I replaced the front 2 ABS/speed sensor lines.
I have been doing more research regarding the Fuse 31 issue ... I found on another forum , that the culprit could be the ABS/DSC Yaw/Rotation Rate sensor under the drivers seat. This sensor could be shorted out, causing the ABS module when plugged to blow fuse 31,killing the control signal to the fuel relay, opening up the relay and stopping the fuel pump.
 

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Your steering sensor can also be shorted. Where you hearing an odd random click when turning the car, it is infrequent and happens for sometime before it actually breaks. They can break shorted and open but the thing to do is look for ABS codes with the correct tool. Unless you have the correct tool to read you can't clear the codes so they will still be there if you look. Could save you a ton of time and expense.
 
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