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  1. #1
    Join Date
    Feb 2019
    Location
    Cape Town, South Africa
    Posts
    2

    Default Electrical communication failure

    Hi

    I have been all over the various forums and donít seem to have come across this issue posted for my particular model. It is a XC70 D5 2009 Tiptronic Auto model. I was driving along and suddenly heard a single knock coming from around the passenger footwell area. The car then lost a bit of power and the ABS and skid control indicator lights came on as well as the red warning triangle and a message stating: Brake Failure Stop Safely.

    After coming to a stop I put into Park and tried to switch off the engine. At first it wouldnít switch off but after pressing the button a few times it switched off but wouldnít release the key. I tried restarting but no joy.

    After organizing a tow truck to my local Volvo mechanic, he at first thought it must be the battery or alternator but none of these showed any issues. Unfortunately his diagnostic equipment couldnít pick up any communication with the onboard computers. So he sent it next door to an auto electrician who has not had any luck either. He reckons it is likely a loose power cable as it canít be that 3 of the ECUís/Comms modules could be broken at once. He has had the car for over a week but is now giving up and suggesting I get it to a proper Volvo dealership whose diagnostic equipment might be able to be better at figuring out the problem. Unfortunately my local Volvo dealership is booked up for the next three weeks, but if I have the car towed there they will see what they can do in terms of squeezing in a diagnostic check.

    The only thing that recently happened to me was that my car was mistakenly filled with petrol about 2 weeks prior to this event. But the engine hadnít been started then as I caught it while it was being filled and it was towed away, drained and flushed and all the filters replaced. So donít think it could be related.

    I see that a similar warning and issue occurs on the P2 model but as far as I can see not on the P3 models. Has anyone come across this issue before on this particular model?

    Thanks

  2. #2
    Join Date
    Feb 2019
    Location
    Cape Town, South Africa
    Posts
    2

    Default Solution

    I thought to let anybody who has a similar problem in future know that I eventually found the solution to my problem. After sitting without my car for a month, the dealer eventually traced the fault to the wiring to the rear differential control module that had been pushed up against the exhaust and had melted and shorted this wiring. Apart from the issues experienced below, the technicians found that the network on the car was sitting at 12V and not 2V and that it was therefore likely to be a short somewhere. Big relief when it was eventually sorted with a very simple solution.

  3. #3
    Join Date
    Aug 2017
    Location
    Pleasanton CA USA
    Posts
    358

    Default

    Thanks for the epilog. Problem resolutions are the real gems of these postings.

  4. #4
    Join Date
    Apr 2019
    Location
    San Antonio Texas
    Posts
    1

    Default

    Yes, I have also searched for solutions to a similar problem, but cannot find any.
    I was in my town recently when on my way back to the house, the car (a 2009 Volvo XC70 3,2 AWD) just lost the power and every warning you can imagine of, started to pop-up on the dash. I managed to get into our yard and shut the car off, I waited about 15 min. and then tried to start it again but it wouldn't turn on. the Power turned on but it warned for pretty much anything there is, so I just shut it down and left it for that day.
    a day later I went out and then it started up just fine, so I moved it out of the way in the driveway to a better spot on our yard.
    a Day after that I went out to start it up and try to see if the problem was still there and it started up but I couldn't move anywhere. I put it in Drive & Reverse, but nothing happened, I tried to rev it but got no reaction on the throttle and all the warnings popped up again.

    I can say that I had been to O'Reilly's a couple of months earlier to do a check up with their electronic reader, because I got a warning for low engine oil level although I had proper oil level in it.
    When the O'Reilly guy were done with the reading he said that it was something wrong with one off the Quote: "Electronic Boxes" in the car.
    Apparently the car has 3 of them, and he couldn't read which one of them it was that was failing.

    I don't know the correct name of these boxes so if anyone knows I would appreciate if you could tell what they are called. It is not the ABS box that the guy was talking about, but some control units.
    I have researched but I have a hard time finding the right units and I live far away from a Volvo dealer so I can't just go there. I might have to take it on a trailer or a tow truck to get it there for an inspection. But for now I just try to get some information.

    I appreciate any constructive ideas that anyone might have to solve this pesky situation.

    Thanx.

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