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DIY PLCD sensor change

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13K views 49 replies 8 participants last post by  Zac Cov  
#1 ·
My PLCD sensor finally came in today so soon I will be changing it out myself. Thanks to those who gave some suggestions. Does anyone think it’s helpful for the group for me to try to add any pics (will be limited space Im sure) and my process afterwards or do we feel like there is already enough on this?
 
#3 ·
Def would be a good addition to the DIY section.
 
owns 2000 BMW M5 DUH!
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#4 ·
its possible to do it without dropping the exhaust, depending on the condition of your engine mounts remove the trans crossmember by unbolting it and itll drop like 2 or 3 inches then put in a series of 1/4 extensions with a swivel on the end and you can take both of the screws out. theyre a 4mm hex iirc. pay attention to the routing of the pcld wiring harness, its ran a certain way and held by a couple of clips.
 
#5 ·
Thank you for that! Thanks to my springs I need a lower profile Jack to reach front center Jack site so I haven’t got it lifted up yet. (Less than 4” clearance)
I’ll check the condition of engine mounts prior as well. They may be original unless replaced when rod bearings and headers done but unsure.
I would love to do as minimal as possible so hopefully I can do like you did.
Did you replace those clips as well and any trouble disconnecting/reconnecting those other 3 connections? If Im not stuck here too late at the hospital I’ll try to begin tonight.
 
#6 ·
Work in progress update* pics included
Car is currently supported by 4 Jack stands, all plastic underbody protection and some heat shield removed. Disconnected two of the easy to access connections and for fun attempted to blindly access the two 4mm hex screws with various flex extension combos to no avail. Figured that was a good stopping point for tonight. Any further tips and advice welcome!

Front Jack Support location I used
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How I Jacked up Rear
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Plastic underbody covering smg removed (8mm) I removed some of the heat shield but believe there was a break in it allowing some to be removed and was only supported by one 8mm on passenger side.
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I will continue my “fun” work after real work tomorrow.
 

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#10 ·
Hahaha, yeah, without the help of oompalompas I’m at that point where I will have to drop the trans. I’m in SC so it’s too hot at the moment to continue but I’ll head out there in a few hours.
—>I am a little nervous about lowering the trans some for access as this will be first time and I’ve seen several different methods and when referring to “just drop rear of trans” are they still fully disconnecting from drivetrain and all or trusting engine mounts and only removing rear brace and allowing it to drop (supported by Jack) like 2-3 inches?
 
#12 ·
Well let me give an update on the progress. I had to go ahead and remove the exhaust (14mm and 10mm) and what feels like 20 more underbody/heat shield screws to expose driveshaft (mostly 8mm). Will need 6” extension at least to reach rear exhaust support brace. Excellent time 🤦🏼‍♂️ to find out small rear support (can add a pic as well) was badly welded and broke during initial exhaust upgrade years back I believe. Anyway, had to make another run for tools. I’m not rushing this progress at all as I want to do it right. I really wish I had you guys close by as this seems like a lot more than I thought for a sensor. I’ll update later and try to include pics that are of value. When all is said and done I’ll have to clean this post up/create new thread and condense for easier future reference. I feel like I need to address these things I’m discovering. Thank you all. Hope to update later tonight or tomorrow.
 
#13 ·
That little sensor has been the biggest pain!! Finally got it out, removed total exhaust. Only needed to disconnect the middle driveshaft support prior to lowering trans which is a must unfortunately. With the trans supported I lowered it about 3 inches making sure not to stress engine support. Had to still have a buddy help guide me with light and a camera to get the 4mm hex seated on the two screws since still hard to see. I managed to drop one in the process of removing and the gremlins claimed it. Below are a few pics afterwards and how trans was supported. Overall it’s all just very tedious. Thank you everyone who offered help. I’ll update again after reinstall. Next question is do I run clutch adaption or drive it first to see how it feels?
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#18 ·
Expert, as in everyone here’s advice, haha, is needed as I have the car all out back together and I’m unable to get the engine to start.

Is there any reason why after a PLCD sensor chance I would not be able to start the car? Like a hard stop?

My first thought was the battery so I went ahead and had it tested and fully charged so that’s ruled out. Could be that I did not fully seat one of the 4 sensors (including the long one that gave me a migraine with the 2 4mm screws)? Side note, I broke the head off one of those screws while reseating (cross-threaded or weak point and I over tightened 🤷🏼‍♂️) but the other was fully seated and tightened.

I was getting an error with my INPA software when I tried to communicate with ECU after replacing the sensor (before I went and got battery fully charged) but was able to still read stored codes but could not clear them. Interesting though only one code appeared now.

Also very interesting and made me feel better was that according to analog values 3 section in INPA my Clutch Main Sensor and Position Clutch Redundant are now within normal limits. Picture attached. I’m hesitant to trust this info as INPA was saying there was communication/script errors and I had not addressed the battery yet either.

I am currently working on troubleshooting INPA/laptop device management settings before attempting to reconnect to the car and check/clear any codes and hopefully be able to run clutch adaption after. Thank you everyone, if I get this car working today everyone who helped here is getting some local craft beer sent to them, I figure logistics out later.
 
#19 ·
To be clear here, PLCD sensor doesn't require the adaptation for the car to start, clutch valve adaptation is must=recommended to get precise clutch operation as much as possible to smooth out clutch engagement.

The PLCD values should be around 650 on the main sensor and around 440 on the redundant sensor ignition on, this is tell us the clutch is closed.

Engine to start, brake is depressed, clutch opened 230 main sensor and 780 redundant sensor, SMG hydraulic pressure is over 50 bar, gearbox is at N, CAS will send 12V signal to starter solenoid, engine starts.

Where is the pictures of Analog 3 with brake depressed and released, fault codes.
 
#23 ·
The INPA error has no effect we all have if using same version, it is language issue.

Those reading bad. The clutch didn't move, was the ignition ON position, even though with ignition ON and brake pedal released values is not good, the values means the clutch is partially opened.
Is the gear in N, put ignition ON try to shift to R or 1st does it shift does the clutch values moves, solenoid on the left side values changes?.
What is the fault code print screen the whole page of the fault.

Tell us more about it, how the car stopped/ malfunctioned/ didn't start, then you started to troubleshoot and found the PLCD fault, or the car stopped just to replace the sensor but still can start and function when the sensor fault is not present?. Both PLCD sensors gone bad means you have been getting PLCD fault more frequently until the car is no longer willing to cooperate.

Those values and clutch slave doesn't follow command also means the shaft is disintegrated and probably feel in the bellhousing. You should have showed us the values of the clutch before you replace the sensor to see if these values is there or not.
 
#24 ·
The INPA error has no effect we all have if using same version, it is language issue.

Those reading bad. The clutch didn't move, was the ignition ON position, even though with ignition ON and brake pedal released values is not good, the values means the clutch is partially opened.
Is the gear in N, put ignition ON try to shift to R or 1st does it shift does the clutch values moves, solenoid on the left side values changes?.
What is the fault code print screen the whole page of the fault.

Tell us more about it, how the car stopped/ malfunctioned/ didn't start, then you started to troubleshoot and found the PLCD fault, or the car stopped just to replace the sensor but still can start and function when the sensor fault is not present?. Both PLCD sensors gone bad means you have been getting PLCD fault more frequently until the car is no longer willing to cooperate.

Those values and clutch slave doesn't follow command also means the shaft is disintegrated and probably feel in the bellhousing. You should have showed us the values of the clutch before you replace the sensor to see if these values is there or not.
Apologies everyone for late response, lol, I just felt so defeated after everything and was busy with work at the hospital so kind of took a mental break from it all. I do have the INPA analog values prior to changing sensor but believe I attached it to another thread.
Here is the prior values prior to sensor change:
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My major concern is maybe somehow I screwed up the Clutch Slave Cylinder trying to install the sensor as it was hard to see and at one point i thought PLCD sensor was inside the hole of the Slave Cylinder so I proceeded to attempt to screw it into place with my 18” extended socket with the 4mm hex screw head secured to end (so I wouldn’t loose it) and didn’t realize until after a few turns that I had in fact not had the sensor in the hole and instead had stuck the socket in there. After some choice words and beating myself up I did get in the slot.
Now for the next possible issue that could be of concern was the two 4mm hex screws to secure the sensor in place. I lost one when removing so instead of waiting for one to be shipped in I received a similar one from the local import tune shop. I proceeded to seat and tighten that screw which was a pain due to limited visibility/clearance and wound up breaking the head off tightening it. I was able to properly seat and tighten the second screw and the PLCD sensor appears to be secure. With everything and the connections “appearing” to be reconnected as far as the sensor was concerned, I proceeded to reassemble everything. With the car back together I proceeded to attempt to start and run diagnostics/adaption but it wouldn’t start now. And here we are….hahaha. I’m just baffled and at a loss as to where to proceed from here.

You guys have been great on here and looking forward to some more guidance. I also got a snake camera so I’ll be able to get a really good look at everything and the wiring as well as maybe that’s damaged after messing in there?
 
#27 ·
Ok take your time, we just need goo data to troubleshoot before any major request.
Also while doing the video with just ignition ON after that start the car and try to engage 1st or R show us what is displayed on Analog 3 and the instrument display, I just need any evidence of clutch movement.
Fault 5007 is shift paddle (-) is it broken? it seems permanently is actuated, it shouldn't, if it does you need to try to unlatch it, you can get access to it, possible it is what stopping the start up. Delete the fault.
To get fault log you need to go to Error and scan to see the details.
 
#28 ·
Just getting home, funny you mention the (-) paddle shifter as it has been broken ever since I got the car and never got around to getting it fixed. Got used to always shifting with the stick and disregarded that. Any idea how to unlatch off top of your head? I’m gonna go look into that and then see if that’s the issue. I’ll run INPA after that and upload the video.
 
#31 ·
We can now rule out the paddle shifter causing any issue now as went ahead and made sure the paddle shifter wouldn’t be engaged when I reattached to the steering wheel and then reattached battery and ran INPA. Cleared codes and now the only code that I can not clear is the 4FA0. Car will still not start unfortunately and attached is a video of INPA analog 3 values with ignition on, brake pressed/depressed, attempting to start and engage any gear including reverse. Hopefully I was able to do properly what you requested and was able to provide good enough audio/visual in the video.

INPA analog 3 had to upload a link to iCloud due to file size.
 
#36 ·
The clutch deviation in the fault log is not much, I been scratching my head in the past week trying to figure why the clutch valve didn't move in response to the brake pedal command to open the clutch, is the brake signal missing? or the clutch valve is not getting signal? or SMG blocking the operation of the clutch.

I asked you to post the SMG status digital values to see the brake pedal command, you can view it and press the brake and see if the signal is reaching the SMG. Check the wiring for the clutch valve on the left side of the transmission, all the wiring connectors on the right side(disconnect and reconnect) multiple times, also cycle the SMG control unit connectors and inspect the pins for cleanliness.

Manually activate the clutch by software SMG>F6 Activate>F2 Valves> choose to open and close the clutch and you can also command the clutch to position itself at the slip point adapted position and to filling position, see what happens and post. All this with ignition ON only, make sure to press F8 before you exit that page, then test the clutch by pressing the brake pedal.

Next you will be required to run the clutch valve adaptation as a last step before going invasive, if it fails the gong will be hitting your head but you must perform it before dropping the transmission.
 
#43 ·
Yes weird that you both having the same issue at the same time. Fail to open the clutch with brake pedal never been in the forum before. Commanding the clutch manually by software is the only way to force the slave to move multiple times to stir fluid in the lines and that will give the slave a push to start actuates normally.
Manually activate the clutch by software SMG>F6 Activate>F2 Valves> choose to open and close the clutch
OP would do the slave extension exercise and report the result.
Recently I came to a conclusion that even not opened systems hydraulic fluid could bubble and caused pump cavitation and as a result air pocket will be introduced causing failure of positive pressure introduction and Inexplicable component failure symptoms. Replacing the seals/O'ring will for sure minimize this condition and improve the system general operation. This one of the reasons I would suggest for any member in process of doing maintenance on the SMG system to replace these cheap seals to improve the system operation, minimize such issues, and help final adaptation to complete.
 
#39 ·
Just a reminder, running the clutch curve adaptation may not be a good advice really since the slave is not moving in a good range and the adaptation will fail and its fault and annoying constant gong will be on all the time till the fault is cleared which will not be cleared until the issue is solved. Instead I would keep triggering the clutch valve by the software multiple times to simulate manual bleeding may help the slave get rid of air pocket if the air pocket is the cause of this issue. After multiple slave extension trial by software check if the range changed to hint an improvement is noted.
 
#40 ·
Im under the car now on my back, only jacked it up from front mount. SMG control wiring under the hood visually seemed goodly but it. I’ll test the relay as well when I get inside. I Have just rechecked all connections and wiring associated with the PLCD sensor and they seem to set and wires good.

You had mentioned about the brake signal, prior to beginning work it seemed like I had to almost push the brake pedal to the floor like brakes were going bad. Could this be related at all to the brake signal and how should I check that? Lol, I’m texting while underneath here.
 
#42 ·
Sounds like you are having a very similar issue to me currently. I have no actuation with the brake pedal either. After download ISTA and manually operation the clutch quite a few times, I was the able to actuate the clutch with the brake pedal, but only a little bit of travel. The PLCD values finally changed on brake pressed pressing. Still failed bleeding and clutch adaptations but I am now able to start the car, get it into gear and drive off. Still work to be done but its a start.
 
#46 ·
Prior to me attempting to install the sensor the car would start but because I messed up clutch slave and pivot (didn’t fully realize until I put car together) the car couldn’t sense gear position and would not start. (Diagnostic showed sensor was now good but clutch readings off, shown above)
 
#45 ·
Sorry for not posting an update in what feels like forever but as of today I still do not have the car back from the shop. The transmission work has been completed but my brake pedal was going to the floor so that’s being addressed since it’s there. A miscommunication between us meant they did not address those and I found out when coming to pick the car up Friday. This has been such a long drawn out headache. As a result, I have not gotten a chance to test drive after the work.
So far and many $$s later, I believe the clutch slave cylinder, dual mass flywheel, pivot, and clutch were replaced as well as maybe some other things that I can’t recall off the top of my head. Waiting for a quote on the brakes. I will give a full update when I finally get back behind the wheel. From talking with shop owner I think it was me that may have messed up the pivot and clutch slave.
Thanks again everyone.
 
#47 ·
Just another late update, still don’t have the car back as the brakes turned out to be more than I thought, being the actual ABS control module had an internal leak and needed to be replaced. That had to be shipped in and luckily the shop was able to get one at much better price than direct from Germany. It’s gonna feel like a whole new car when I get it back….by the end of this week?🤞🏻