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Flameon, how old is your battery? Start by checking to make sure your battery is good and alternator is holding power steady during running.. The hydraulic pressure sensor code isn't common, I think I've seen one of those sensor fail on this board, ever.. But check to see if that connection is good and plugged in. Might need to change that sensor out if that code keeps coming back.. Its cheap and easy if that is the case. That pressure sensor is what i believe is causing the other two codes you see.

4F40 Hydraulic Unit Under Shooting of Pressure Range
4FA0 Activation, Clutch
5101 Evaluation, Hydraulic Pressure Sensor
 

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I just went through this and fixed my car. Had the same codes, all you have to do is add SMG fluid and then use a program such as Impa to bleed it. Did this with mine and fired right back up. Has never felt better. For reference I have 58k on mine.

Happy to help feel free to PM me. First thing is get it away and far from the BMW dealer.


Does this imply we should change our SMG fluid at some interval to insure that it doesn't get low and kill the pump? I need to get my diff fluid changed and I was considering having the SMG fluid changed as well, but was unsure if it's recommended to do so or not.
 

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Does this imply we should change our SMG fluid at some interval to insure that it doesn't get low and kill the pump? I need to get my diff fluid changed and I was considering having the SMG fluid changed as well, but was unsure if it's recommended to do so or not.
When my fluid was low i was getting 4F40 (SMG: Hydraulic unit: undershooting of pressure range) every now and then... Now i check the smg fluid once a year. When the fluid is really low, thats when you cant shift as you dont have enough fluid to pressurize of course, that gets dangerous.
 

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Should it be changed or just checked for level periodically? I couldn't really find a recommendation for SMG fluid change, but I may have just overlooked it.
 

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replaced both relays under the hood the salmon and black relay. Then the big fuse by the black relay was blown also, Replaced that fuse. Still nothing. Car still does not start. Any ideas? smg motor?
 

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Yeah man i took it to bmw so now they say my pump unit is good but there is a leak of the pressure fluid. And the bmw tech can not locate the leak
 

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BMW doesn't diagnose the Hydraulic system component individually, they change the whole unit. If you have the extra fund you can have it replaced and get it over with. If not, then you might have pump internal leak, and this can be resolved by changing the heart shaped seals, also it could be the accumulator, you can test that with ISTA/INPA diagnosis system.
in order to have an idea we need to know what is the symptoms and what is the fault code the SMG ECU is throwing.
If you have the software, search here for similar issue or post new thread.
 

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2006 BMW M5
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I dont have the funds for a 20,000$ fix lmao.. but i will try the seals and accumulator i will make a new thread of this journey and let my v10 owners know my experience and a solution thanks for your knowledge 🙏🏾
 

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I don't think the hydraulic pump would cost 20,000, some guys here got lucky and the bill was around 4,000. unless you talking about changing the complete transmission assembly.
Diagnose first before changing parts, because you may have leaking clutch slave but that required removal of the transmission. Start with explaining symptoms and fault codes.
 

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I don't think the hydraulic pump would cost 20,000, some guys here got lucky and the bill was around 4,000. unless you talking about changing the complete transmission assembly.
Diagnose first before changing parts, because you may have leaking clutch slave but that required removal of the transmission. Start with explaining symptoms and fault codes.
The new OEM pump assembly is $8,233 plus tax if applicable.
 

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Waiting to see if the dealership i bought it from is willing to fix it or take the car back only owned it for 3 weeks lmao bullshit dealers these days
 

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Zedtt, you are right about the official price, I said "some people GOT LUCKY" to have it changed for that price, may be that happened under certain circumstances or special discount, if their statement were true. I have seen similar info on the board.
 

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I got my car back from bmw today it turns on and i can drive it with no issues and they said there is nothing wrong with my hydraulic unit as a whole But somewhere is losing pressure internally but i drove it today washed her and gassed her up after a week. How the hell does a tow truck driver get the car out of nuteural but the top of the line mechanics at bmw couldnt???!
 

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Best solution to your problem based on the error you mentioned is to remove the pump and change the hearted-shape seals, providing the motor for them is working properly, and the accumulator passed it's test with the software. There is users here done the repair for the pump successfully with pictures.
 

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To me it sounds like pump motor brushes. Codes match and it is an intermittent issue that gets worse eventually. A leak would be there at all times, worse when hot due to thinner oil
 

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This kind of problem required close monitoring of the pressure to determine which way you hit first. It is cheaper to change the seal first if labor is not a factor.
 

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This should be the standard SMG service when you have problem. Clutch solenoid seals, Accumulator, Motor refurb or replacement, oil and relays. It's all in the same area and none of it will break the bank. After that is gets more expensive and more complicated.
 
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