Replacing ABS Control module 996 355 955 BX

This is my first post as a 911 owner. '02 996 Tip Cab.

I have an ABS control unit fault that means the motor is running continuously and the PSM and ABS lights are on.

There are a multitude of part codes for this unit it seems. Mine has the 4 pipes and Traction control. I see a lot of identical looking units with a 996 255 755 code are these interchangeable?

Is this a big job to do yourself? Is there a DIY guide on here or does anyone have experience of changing out one of these units? What are the gotchas and any advice on equipment needed bleeding systems etc.

I am on a tight budget and nearly fainted at the 4,414.04 ex vat and ex labour quote from Criddocks!

I have seen a number of used and guaranteed working units on ebay etc. for a fraction of that price some under 100 pounds.

Anyway any help and advice/guidance would be appreciated. I have many thing sto do on this car and I hope I can learn a lot from the experts on this forum.

Cheers
Spart

Are there any local (and recommended) smaller independent specialists? I would expect these are more willing to fit 2nd hand parts.

Only 'gotcha' I've read about is bleeding the brakes where you need to activate the ABS pump to clear air. To do this you need a laptop and relevant software.

Relevant software?

Paynewright said:

Are there any local (and recommended) smaller independent specialists? I would expect these are more willing to fit 2nd hand parts.

Only 'gotcha' I've read about is bleeding the brakes where you need to activate the ABS pump to clear air. To do this you need a laptop and relevant software.

Click to expand...

Many thanks for the reply.

You mentioned relevant software. I have looked around for Porsche Diagnostic tools and software as I need to replace the following modules according to a scan that was done on the car by Criddocks before I bought the car from an Insurance disposal sale.

996 653 101 IX EFR AC Control module
996 641 981 76 70C Instrument cluster
996 355 955 BX ABS module
996 624 102 06 Drivers window motor
996 543 015 06 Rear window lifter with motor Left
996 543 016 06 Rear window lifter motor Right

So I will need some kind of system that will recode all the new modules ot the car. The Duralogic system does not seem to have the capability to deal with ABS etc. modules.

I will start another thread but is there any open source stuff that will allow me to interact with the vehicle systems?

Cheers
Spart

996 and Boxster 968 compatible parts?

It looks like the PSM cars are limited to the following units. Does anyone know if I can simply substitute a Boxster 968 part?

Seemingly from the Porsche parts catalogue these are interchangeable 996 compatible parts:

996 355 955 46
996 355 955 52
996 355 955 54
996 355 955 62
996 355 955 BX

These are all for model designation and option M338 (Rear Wheel Drive)/476 (PSM)

It looks like for boxster 968 parts then substitute 955 for 755 e.g 996 355 755 62

Are there any experts on here that can help please.

Cheers
Spart

can we just take a step backwards for a min please ..

Has the ABS CU actually been diagnosed ?

Can you list the fault codes that are currently permanent ?

Motor running permanent .. do you mean the pre charge pump ?

https://www.deroure.com/diagrams.asp?TBL=2605&MAK=3&MDL=25&SMA=0&SMO=0&ST=&SC=0

17 on the link ?

996 and 986 share some parts .. the software will be different though ..

To get an accurate part number for any part you phone an OPC .. give them the chassis number and they will tell you the part number and cost .. you can then source from where you wish at that point .

If a part number doesn't match then it wont fit .

It will need coding .. Durametric can do some things but i can't say if abs coding is one of them .. an indy however can code them as we have more expensive testers .

You also have a rather expensive list of items to replace .. can you share any info on the window lifters .. as these won't work if there is a roof issue and also the instrument cluster .. why has it got to be changed ?

In short i don't mind spending a bit of time helping out if possible ..

Only here from 7-9 pm though so please be aware of that .

deMort said:

can we just take a step backwards for a min please ..

Has the ABS CU actually been diagnosed ?

Can you list the fault codes that are currently permanent ?

Motor running permanent .. do you mean the pre charge pump ?

https://www.deroure.com/diagrams.asp?TBL=2605&MAK=3&MDL=25&SMA=0&SMO=0&ST=&SC=0

17 on the link ?

996 and 986 share some parts .. the software will be different though ..

To get an accurate part number for any part you phone an OPC .. give them the chassis number and they will tell you the part number and cost .. you can then source from where you wish at that point .

If a part number doesn't match then it wont fit .

It will need coding .. Durametric can do some things but i can't say if abs coding is one of them .. an indy however can code them as we have more expensive testers .

You also have a rather expensive list of items to replace .. can you share any info on the window lifters .. as these won't work if there is a roof issue and also the instrument cluster .. why has it got to be changed ?

In short i don't mind spending a bit of time helping out if possible ..

Only here from 7-9 pm though so please be aware of that .

Click to expand...

DeMort,

Thank you so much for the offer of assistance 911's are new to me so learning on the job. My head is swimming with part numbers and decoding the official porsche parts catalouge. I am mobile at present but will ping you the full details. Cridfords did the original diag for the previous owners Insurance and the list of parts came from then with an eye watering quote I have asked for the detailed P codes but nothing as yet. The issues were caused by the owner attaching his charger in reverse polarity. I can see how that might happen as both battery leads are black But he had owned it fur 10 years.

The car starts and drives perfect, The convertible roof works perfectly even though the rear windows lifters strengthening etc are out. It is a full history car with an amazing documented past going back to original supplying OPC in 2002.

More to follow.

Cheers
Spart

Ahhh i had wondered if reverse polarity on the battery was the issue ..

Alarm CU and possibly dme are the 2 main problems with this .. along with pcm / radio but that doesn't really matter ..

Instrument cluster .. rare if that needs replacing along with the PSM cu ..

What we need going forward .. you need to get a fault code reader and you need to give me the codes that are present on every system.. that will give me something to work with .

If the car doesn't see the roof in the closed position it wont operate the rear windows .. i suspect it's not lifters for the windows you need but to sort out a roof fault .

Again with instrument cluster .. what actually doesn't work ? a new cluster is fortunes so we need to see what the actual fault is .

Fault codes young man and on every system .. that's what i need !!

Look at buying a durametric system .. that's about the best and cheapest you can get without moving into the realms of a piwis clone .

If it helps .. a 997 reverse polarity and it destroys about 6 CU,s .. hopefully this is less than that !!

The only data I have at present is the eye watering quote with a list of these parts:

996 653 101 09 FFA AC Control module
996 641 981 76 70C Instrument cluster

One of the following:
996 355 955 (755) BX
996 355 955 (755) 46
996 355 955 (755) 52
996 355 955 (755) 54
996 355 955 (755) 62 ABS module (This is the identical unit to the one currently fitted)

996 624 102 06 Drivers window motor
996 543 015 06 Rear window lifter with motor Left
996 543 016 06 Rear window lifter motor Right

Cridfords did not supply the owner with a detailed print out of fault codes. I am chasing them to see if they kept a detailed record I would hope so with the quote they produced!

In terms of operation.

The car starts and drives perfectly.

The roof system seems to operate perfectly, seat belt sensors, rear spoiler, boot sensors. The Cluster seems perfect, all warning lights seem to work. all LCD digits seem perfect the dials seem to reflect reality, revs, time, temp, pressure, Speedo etc. With my cheapo ODB2 sensor pluggedin I can see most engine and dynamic info, revs etc. It drives perfectly albeit with no ABS or PSM, Passenger door works perfectly, window drops down on operating the handle and comes back up under the seal. You can retrain it once the battery has been removed and put back and it seems to remember its settings once trained. The Alarm system seems to operate perfectly, Remote central locking, remote roof operation etc. It had 2 brand new 3 button keys on August 2019 as the old ones were getting temperamental the previous owner said.

The AC unit is toast I think as it blows fuses as soon as plugged in, but that should be a plug and play item as long as identical part and ver 4.1.

The audio system seems to be toast. The CDR-32 is dead, I cannot find a way to test the Bose Amps, the main one being 996 645 339 00 and the smaller additional one being 996 645 341 00. These 2 parts tally with the official Porsche parts catalogue for the 02 M380 cab so I assume these were factory fit and it is a M490 option (non MOST) and has a total of 3 plugs. The CD Changer is missing and I have a fly lead in the frunk with 2 x RCA's and One 2 pin round plug, which I am assuming is for the missing CD changer. In the cockpit I have a Green, Blue and Yellow mini ISO plugs assembled as one block, then a full size Brown ISO and then a Black ISO which looks like the power speedo tel mute etc.

I can power up a Ferrari Becker unit (an old one from my Ferrari 360 Spider) that looks identical to the CDR 32 all plugs fit and functions seem to work, Radio, CD (built in) etc. But no sound from any speaker.

The rear window lifters on both sides seem to be a problem. The Drivers side pops fuses instantly you plug it in to the rear loom, the passenger side can be plugged in but simply clicks on operation of the switch. Any advice on bench operation of these units would be great.

The drivers door is currently taken apart. It had a brand new Porsche regulator in August 2019 but the motor is inoperable and just heats up, clicking can be heard on operation of the switch.

Cridfords had left it in a sorry state with bolts, nuts, clips trim simply chucked in it, plastic trim stuffed in the frunk and all over the floor. Passenger Seat unbolted and bolts chucked in the footwell. It's going to be fun working out what came from where! Such a shame as they had looked after it for 10 years and the owner had spent approx. 4K over the previous 18 months. New Sports exhaust system etc. It is a lovely car, seriously well looked after for all its life. Just hoping I can get it back to its former glory without going broke in the process.

I can't seem to find a way to upload pictures to this forum at present. Anyway that's about it for now, thank you and apologies for the long post, please forgive typos etc.

Cheers
Spart

Various pictures.

Regarding the ABS unit, have you thought about getting it tested and repaired, I have used a local place a couple of miles from me that gets work sent to them from all over the world. You can send it for testing and it saves searching for the correct unit for yours.

They only charged me £40 to test mine, there was no fault found but they did tell me what would be wrong and I fixed the problem for a couple of quid.

https://www.ecutesting.com/categories/abs-pump-modules/

infrasilver said:

Regarding the ABS unit, have you thought about getting it tested and repaired, I have used a local place a couple of miles from me that gets work sent to them from all over the world. You can send it for testing and it saves searching for the correct unit for yours.

They only charged me £40 to test mine, there was no fault found but they did tell me what would be wrong and I fixed the problem for a couple of quid.

https://www.ecutesting.com/categories/abs-pump-modules/

Click to expand...

Sounds great. What are the implications of undoing the pipes from this unit. It has had power disconnect for a while. Should I expect high pressure discharge? Do you have any further info about removing the unit and what to watch out for?

Thanks for the info though. The cheapest unit I can find is over a grand!!!

Cheers
Spart

It wasnt on my 996 but the missus Seat Ibiza, I just took it off, I don't think there is any pressure in the system that I remember and when I refitted it I just bled the brakes as normal, this was a few years ago and since then I have heard you need to open the pumps valves with the specific software to bleed them properly.

I think we can safely say this was a wee bit more than just an incorrect terminal jump start ..

No idea how but items have blown that shouldn't have .. well .. let's just say i've done a handful of these over the years and not seen this amount of damage .. 997 and yup .. its total carnage when this happens but not a 996 .

Ok then ...

Instrument cluster .. leave it for now , there doesn't appear to be a fault so it might just be a fault code they have based it needing a new one on .. they are dam expensive so leave for now .

A/C .. yup a new unit .. possibly other issues but logic dictates its only that .

It might need coding , i can't remember off hand .

the radio has a fuse in the back of it , i'm guessing you have checked that and the main feeds / earths to it are ok ? if so a new head unit .

Amp is possible , not really a bench test item as you would need a radio plus speakers on a bench .. as a new head unit is probably needed then i would start with that .. then a new amp if it is dead although you can have any amp / stereo system fitted that you want .

996 amps have always been a bit flakey !

The Ferrari radio might not be compatible so it's not a definitive test for a faulty amp .

Both rear window motors will be required .. not the actual mechanism though .. ebay sell them .

O/s/f window motor is required .. again ebay ..

With all of these its the control unit part that's failed .. the motor will be fine ( it works with reversed polarity to go down ) but you can't get just the electric part as its one unit .

ABS unit .. it has a terminal 30 and as such anything with a permanent feed can be damaged ..

It can just be unbolted and sent for testing .. a new one or second hand will need coding and probably a tester to bleed the brakes .. it all depends on if its been drained .. sometimes you can get away with this on a second hand unit .

Any pictures of nuts / bolts or any item you have a question on then feel free to email me them .. i can always resize if needed and post it here .

[email protected]


EDIT ..

Manual and wiring diagrams are here if needed ..

http://911uk.com/viewtopic.php?t=83491

@deMort

Turns out it had 24 v through it!

I have now sourced the following:

AC module - exact part number and firmware
O/S Rear window motor - Exact year and part numbers
N/S Rear mechanism and motor - Exact year and part numbers
O/S Front Window Motor - Exact year/Model and part
339 00 Amp - Exact Year and Model
341 00 Amp - Exact Year and Model
CDC-3 Exact Year and Model - Cos why not!

ABS Pump discussed with the repair guys in Derbyshire. Control part on its way to them to be fully rebuilt, should come back ready to fit no recoding required assuming they can access the eeprom data that is on it for my car. Fingers crossed. Big shout out to @infrasilver Top Man! Total cost 155.00 + vat Free collection and return.

Note to moderators those guys should be on a sticky on every forum!!!

So when parts get here I may need some advice refitting the various tub of panels plastics bolts and working out what goes where and how it fits.

If anyone has a set of good pics of what it is supposed to look like in the frunk and rear quarters that would be great.

Thank you for your help.

Cheers
Spart

Strangely enough i had a Boxster that was jump started by a Bus a few years back .. that was a 24 volt jump start !

It would explain why the window motors have died though ..

Couple of things that i have seen in the past and just to make you aware ..

Tiptronic control unit can give problems but several weeks after driving be it fault codes and limp home mode or a battery drain .

Alternators again can cause issues so at some point check the charge rate to the battery engine running .

Pictures of anything to my email please and i'll do my best .. as for instructions then download the manual first then feel free to ask as any of us will chip in as to how to replace various items .

I would also suggest google for images of the various parts .. i don't have many pictures at home of things like this so when answering questions here i often google the item and then link the picture .