XC90 ABS Fault

[galloot633]

Originally Posted by gasc2188

Thanks Dave,
I've not had the XC90 long and this problem has almost become a personal vandetta to sort it out :-) The more I think about it, the more I think its the module. What threw a spanner in the works is BBA tested it and said it was OK but couldnt be 100% sure it was without faults. Which is like saying it could be OK, but on the other hand it could be faulty. Having said that, sometimes the car is fine and doesnt present the "Anti Skid Service Required" and doesnt go into the limp mode, so it could be that when BBA plugged it onto their testing rig, it was behaving itself. It does seem strange though that before taking the module off it had a red triangle on the dash and saying "Brake Fault Stop Safely". Having sent it off to BBA and then putting it back on the car the Brake Fault stop safely message has never come back. Im thinking that with manipulation at the multiplug by taking it off, its moved the pins fractionally on the PCB inside the module and created a different short circuit or whatever they are called. I've not done anything else to braking system so I cant think of any other explanation. Thinks it definitely worth a try and all its going to cost me is a tube of sealant so not much to lose. Thanks for your advice and help mate, I'll let you know how I get on.

good luck with that, out of interest I ran my car for a week with the module off, I got the abs, emission and traction warning on constantly , but that was all , but I had to use my elm interface to clear one fault , I think it was the emission light, as for checking the unit , if yours is the same fault as mine its hard to simulate " on the bench".
dave

[gasc2188]

Managed to get the module apart, the small revolving circular dremmel saw was a handy to get it apart, but I would imagine it would be easy to cut into the printed circuit board if I wasnt careful. The circuit board was extremely intricate and not like anything I've seen on any of the other threads. The pins which plug into the multiplug could be seen protruding through the CPU, although were solded on the other side where you cannot get to. However, I was able to check that these joints were ok with my multimeter. I checked everything using a magnifying glass but there was nothing obvious and the solder joints were approximately 1/4 mm - 1 mm in diameter and just too small for me to tackle with my limited skill with a soldering iron. I've read that the modules on these 2005 models are better than they used to be, but many company's say theyt cant be repaired, and I dont really know why. But also I've read they are coded to the car so I cant try a second hand one on my car. Any even if i got one and attempted to get it re-coded, I've heard that once a BCM is coded, it cannot be coded to anything else....so only option is a new one :-(

Anyway feeling a trifle depressed with the whole thing, I took myself off to the local Volvo dealer thinking I may be able to pick his brains for some ideas. The bloke there is quite good and has been to Sweden for courses on specialist Volvo matters and has shed loads of experience. I left feeling more depressed. He said that without plugging it in to the Volvo diagnostic computer he was not able to give me a definitive answer, which is fair comment really. But he said it could be a abs problem and a transmission problem too. I'm quite comfortable with sorting out the ABS, but the idea of a transmission fault is very worring beacuse of the cost implications.

What he did say is that it could be the area between the bulkhead and the engine bay (where the windscreen wiper motor and gear is), this area sometimes fills with water because drain holes get bunged up, and it could be that watter has collected and corroded the terminals. I intend to check this out over the weekend.

It seems strange that the message "Anti Skid service required" comes up and then and only then is the limp mode activated. Often there is no warning message there and then no limp mode comes on. So in conclusion my thoughts are......abs problem triggers transmission limp mode. I'vre read on other threads that the abs BCM has links with the transmission module and if the abs is faulty it will trigger false codes with the transmission causing it to go into limp mode. The gear box is extremely smooth and works without problem. Anybody else know about corroded terminals or this limp mode situation.

Thanks for everybody who gave advice re the BCM repair, it was definitley worth a go. I re-sealed it using my glue gun which has formed a good seal.

[gasc2188]

Thanks for everybody who has offered help and advice. Just collected my XC90 from the dealer with results of the Volvo diagnostic. The results are much more detailed than the Launch X431 and basically the results show the diferential control module is "off the network" which is throwing the code that the BCM isnt communicating. Im going to get the area stripped down this weekend (weather permitting) to see if there is anything amiss and the module is receiving power. Apparently I am told there is quite a lot of wiring underneath the rear seats. If its this diferential control module is faulty, they are £1480 from Volvo and they are coded to the car, so you cannot get a second hand one from the dismanter's. I wonder if BBA remanufacture/repairs them, or if anybody knows if anybody does. I will keep you posted what happens

[XCF]

New Differential control module on ebay - starting price of £100

http://cgi.ebay.co.uk/ws/eBayISAPI.d...m=320585872370

[gasc2188]

That sounds spot on thank you. I have taken my module off in an attempt to match part numbers and want a bit of advice if anybody knows. My module is manufactured by Siemens and bears the numbers 5WP22229-01 and HAP511 0160 and then finally 105383-01. There arn't any other numbers, and nothing I would recognise as a normal Volvo part number. I rang Volvo up and gave them my registration number of my XC90 which is an 05 (25/5/2005) plate. They gave me a part number of 30787954. I know part numbers can change, but wonder if anybody knows whether part number 30783132 is the same as 30787954. I just dont want to get the wrong thing and would appreciate somebodys superior knowledge. Thank you for anybody who can help.

[Rainedon]

Gasc, after a tad of Googling I found this site which allows multiple part number searches. The 30787954 part is indeed the module.

You may be able to locate all the part numbers you require here, then source them in the UK.



http://www.volvowholesaleparts.com/p...&siteid=213784

[gasc2188]

Hi,
Finally managed to repair my ABS fault on my XC90, although it wasnt really an ABS fault. Just wanted to share my experience with everybody just in case it helps. If you've read all of this thread, you will see that the car often flagged up the message "Anti Skid Service Required" when the car was started. The car would then often go into limp mode (stick in drive 3, a "-" where gearbox mode display should be). The limp mode could be cleared with switching car off and locking it with remote and then starting up again. Unfortunately the "Transmission Service Required" message would be displayed for the rest of the day. Sometimes it had both anti skid and transmission service messages displayed and sometimes just the transmission service message. Somedays the messages wouldnt appear, but one thing is for sure, if there was no messages on startup, the car would not go into limp mode. The car went to Volvo to plug into the diagnostic and the result was the DEM (differential electronic module) was off the network. I took the car away, armed with this information. I checked to see if the DEM was receiving the 12 V supply at the multiplg that plugs into the DEM itself. The 12 V was there no problems. Its worthy of note that the multiplug has a rubber boot around it. These can fail and not form a good connection with the DEM. They also come loose. Mine was fine but thought it worth mentioning. I took out the rear neaside seat to check the wiring below there. This was fine. I then emailed BBA Remanufacturing in Kent (UK) and asked if they could check these DEM's and repair them. They wouldnt commit themselves but they asked me to send it them. I removed the DEM from the car, which was a bit of a pig to get off. It is held in place by two 5mm bolts. They were really really tight and the first one snapped and I had to drill it out. Watch your eyes, i got metel in mine and ended up spending 3 hours down the A&E. I then sent if off to BBA. After about a week and a half, they rang me back and said the engineer had got it on the bench and had found a problem with the circuitry and wanted my permission to go ahead with the repairs. The next day it was returned via UPS. The repair cost me £128 which included the posting and packing, which may sound a bit expensive, but a new one is £1480 and then another £70 ish to code it to your car. So I was pleased with that. I put it back on the car and bingo, no problem, no limp mode and no messages.

You can check your modules if you hold the "Read" button at the end of your indicator stalk and press the rear fog light switch on and off twice (quickly). Wish I knew that before I embarked trying to sort out this problem.

Hope this helps

[gasc2188]

Thanks for everybody who offered help and advice

[Ron_XC90]

Good to hear that you managed to get it repaired. It's so common these days just to replace parts even if £1500,= Great job!

[kiteski]

Interesting thread, my 6 month old XC90 came up with Brake Failure - Stop Safely warning last night. Followed by Anti skid service required, and the rev counter and speedo dropping to zero and then flicking back again.

Car is a manual and appears to drive fine, off to the dealer tomorrow as under warranty!

I am assuming its ok to drive and this is some kind of electronic warning, rather than the mechanical brakes being at fault?

cheers,

Greg