BMW M5 Forum and M6 Forums banner

1 - 20 of 36 Posts

·
Registered
Joined
·
19 Posts
Discussion Starter #1
My 2006 BMW M5 has run perfectly since rod bearing and all valve springs replacements about two years ago and Throttle actuators a year before that. It has 150k kms. In the past few months I have noticed troublesome shifts on occasion but only occasionally. In the past month things have deteriorated rapidly beginning with a no start event with a code 4FA0. The transmission would shift between N and 1st gear but the car would not start. After a slight push it did start normally and ran well but shortly after the first drive since the "No Start" the transmission randomly began to shift into neutral typically at about 50 kms in 3rd/4th gear. A COG would appear and the message transmission problems car may not restart etc etc. It remained in neutral for 10 seconds and returned to the appropriate gear for the reduced speed (ie. would shift down to 3rd from 4th or to 2nd from 3rd) the message would also then disappear. At times on stopping at a red light it would completely stall with the COG showing up on the dash and the transmission problem warning light appearing. I returned home as the stalling and random shifting to N made driving frustrating and annoying for those behind me.

The next day, a Sunday, so less traffic headed out to see if the problem persisted. To my surprise it started fine and all appeared back to normal until I hit 40kms and the tranny slipped again into N. Again only for a short while with it back in gear and the message disappearing on the screen as well as from the Check Control screen. Anyway continued on my way and all seemed fine for a 30 minute drive (cautious reasonable speeds and shifting). Suddenly it again shifted into N, Message returned and Check Control screen warning issued, only this time entered limp mode. After a short while returned to a gear and messages disappeared except for limp mode.

On return home which was filled with repeated N shifting etc etc, I checked for codes which were again 4FA0, 4F40, 4F42 and this time 2B57. I cleared the codes and went on the hunt here for an answer where I learned it was recommended to replace the SMG relay and fuse, which I did. I then performed the SMG reset (paddle pull) but the slipping remained but the car didn't go into limp mode as I was driving ultra careful/slow. I should mention another code showed up on one occasion much earlier as 5101 but is no longer showing. In any event I have also noticed the SMG pump priming as I unlock the car is very inconsistent and at times non existent but mostly short spurts on unlock and no longer the longer whine which I had heard previously.

Please please HELP me get this beast back to it's fabulous working condition this is driving me insane..... based on what I've read the solutions rests in completely replacing the SMG hydraulic system or replacing the SMG hydraulic motor or simply the PLCD. Really not sure how best to proceed.
 

·
Registered
Joined
·
431 Posts
Just work your way up. Start simple.
 

·
Moderator
Joined
·
2,069 Posts
And this one to refurb your current motor:

 

·
Registered
Joined
·
526 Posts
Original clutch or replaced already?

Your pump is likely on its last leg if it’s original, but if the system is holding pressure or was already at min pressure, that why you may not hear the sound when opening the door. It doesn’t just run for the hell of it, it runs because it detected the system pressure was too low and will stop when it senses adequate pressure.
 

·
Registered
Joined
·
19 Posts
Discussion Starter #6
Thank you for the quick response all. Gmtegear are you suggesting the priming is normal and the pump motor may be fine? If so, any thoughts on what might be the root cause of my problem. Do the codes provide any insight. Replaced the clutch a couple years ago.
 

·
Registered
Joined
·
526 Posts
The motor does weaken and die because the brushes wear out or stick in their holders. That will cause lack of system pressure, which is a code it self. Lack of system pressure can then cause allot of issues.
 

·
Registered
Joined
·
19 Posts
Discussion Starter #8
Well the mold is cast and appears the best advice is to replace the pump motor. Any thoughts on where I might get the best price? The BMW dealership here is looking for $1,262. Canadian ????? The part number is 23-01-7-841-032 I believe.
 

·
Registered
Joined
·
236 Posts
Well the mold is cast and appears the best advice is to replace the pump motor. Any thoughts on where I might get the best price? The BMW dealership here is looking for $1,262. Canadian ????? The part number is 23-01-7-841-032 I believe.
smgsociety.com has it for $300 euros

Also, you can take it apart and clean it, and make sure brushes are not getting stuck Instead of getting new one.
 

·
Registered
Joined
·
526 Posts
Based on the 2 motors I tore down, at this mileage you will have very little brush life left, so best to replace the brushes or just do the whole motor.
 

·
Registered
Joined
·
19 Posts
Discussion Starter #12
HUGE thank you to Dmitry911 and gmtegear for pump suppliers other than the BMW dealer which quoted $1,262. plus taxes. Two excellent supply sources both priced the same once shipping/duty included. I ordered the pump motor and will report back next week once installed.
 

·
Registered
Joined
·
19 Posts
Discussion Starter #13
HELP.....Indy replaced the pump motor only to discover the pump itself would not work and confirmed the old motor was fine. Appears as soon as the motor is tightened into place it will not operate the pump. On the hunt for a new pump to resolve the issue. Any thoughts on this would be appreciated. Not sure if the pump is actually the entire hydraulic unit or a component of it, so would appreciate feedback on what part I am actually looking at. My searches seem to all point to the full $10k hydraulic unit. Also, would be helpful if I could be pointed to suppliers like the ones for the motor.
 

·
Moderator
Joined
·
2,069 Posts
The codes you described are set when the motor starts to act up. It is not a hard failure (i.e. it fails intermittently, especially when hot). So if your indy says the motor works fine well yeah... it works most of the time so I'm sure it'd appear to work fine when taken out.

Seems most problems on reassembly are due to the coupler not properly installed or aligned. Not that it should matter but what motor did you end up buying?
 

·
Registered
Joined
·
19 Posts
Discussion Starter #16 (Edited)
If in fact the coupling was properly installed/aligned (still need to confirm) is the attached image the pump I need? It doesn't seem to be sold separately though, as I can't find a part number anywhere. In any event, is this the actual pump? If so, the challenge will be finding it with alone.
 

Attachments

·
Registered
Joined
·
526 Posts
The pump itself is not sold as a separate part. It rarely is the true reason of failure. This pump and it’s design are very robust and used in a lot of situations where hydraulic pressure needs to be generated. I (and others on this board) have taken a part the pump and have not seen this to be the actual failure. The SMG motor powers the pump and pressurized fluid then flows out to the accumulator. We do know that the MOTOR is a common source of failure. As mentioned above, the motor failure is often intermittent. There are several situations where when inexperienced ppl try to remove the pump to access the motor, the unscrew the wrong screws and then reassemble the pump incorrectly. Also it is common to install the coupling incorrectly, it is supposed to goes on in one way, but it can be put on backwards and then cause the motor/pump to bind up.

it could be that your pump is trashed but PRIOR to any one getting to it, it mostly likely was fine. A bad pump would consistently produce low pressure or bind if garbage got ingested to it. If you did have garbage I your hydraulic system then the whole system must be replaced, because now you have crap that will continue to circulate and damage the new pump. That’s why BMW only sells a completely new hydraulic system and not just the pump.
 

·
Registered
Joined
·
526 Posts
Also it’s worth noting that no BMW dealer has the right experience in just swapping out pumps or rebuilding pumps. There may be one or two indys out there that are competent in getting into the fine detail required. When dealing with hydraulics, you have to be meticulous and do this in a very clean environment. The pump is made to very tight tolerances so debris and mid-assembly is not unusual.
 

·
Registered
Joined
·
431 Posts
When I serviced my motor it took several attempts to get the coupling just right. Mine had the same problem, as soon as the bolts were tight the motor would not run. I had to dress some burrs on the motor and coupling before it bolted together and ran properly. As far as the pump goes you would likely have to buy and entire HPU.
 

·
Registered
Joined
·
19 Posts
Discussion Starter #20
Thanks for the info....I will visit the shop tomorrow and share the views. I hope they are open to discussion and further troubleshooting as it's clear the pump itself is NOT likely the issue.
 
1 - 20 of 36 Posts
Top