2005 xc90 cem problem

[hannah93]

Hi,i have a 2005 xc90 2.4, I replaced my alternator and battery as it was flat every morning. well this didn't change anything and the car continued to go flat by morning (after jump starting it would work all day no problem).
one morning about 2 months ago I went out and attempted to start the car but as usual it didn't start but did make the usual cranking sound, I then changed the battery to a fully charged one I had been given, I then went to start the car and it didn't start nor make any noise atall, just the ignition comes on.
I was advised that it is likely the CEM so I sent the modual off to a company who told me they fixed it and the problem was that it had water damage. when I put the CEM back on my car nothing had changed. I then got advice from a mechanic friend and he had a friend who specialised in the ecu/cem, I send it to him and he has told me that the cem has lost all its data and is corrupt and has now sent my CEM back to me. I have now been told that I could replace the whole ECU kit with the CEM and my car should then start? so far I have spent over £500 trying to fix it and its driving me mad not having a car. I would appreciate any advice anyone could give.

many thanks, Hannah

[Moose Test]

Originally Posted by hannah93

I would appreciate any advice anyone could give.

STOP.

Take it to someone who has the relevant experience and tools and who can perform a proper, logical diagnostic for you. That's either a local Volvo dealership, or a local independent Volvo specialist. In the case of the latter I'm sure someone on this forum will be able to recommend someone local to you.

As you've found, just throwing expensive parts at it and hoping that one of them 'sticks' isn't getting you anywhere and has possibly already cost you more than if you'd taken it to a main dealer at the beginning.

Hope you get it resolved without too much additional expense.

[cheshired5]

I'd be going back to the half wit professionals and asking why some basic multimeter tests weren't done on the battery and alternator and why they didn't do a parasitic drain test like this one.
Changing and charging for something which isn't faulty is basically fraud.

[XJSDriver]

Agreed, but before spending any more money I would get a refund from the company that said they had fixed your CEM and threaten to report them to trading standards if they refuse; Cheshired5 is correct that this smacks of major incompetence - any decent ECU repairer downloads your vehicle's data from the ECU before repair or if they cannot, inform you that they cannot and discuss your options before proceeding.

[hannah93]

Thankyou all, the second person I sent the cem to told me that the first people would have known it wasn't going to work and I should be having my money back, I called them and they told me they wouldn't refund me because the cem was clearly water damaged and they fixed it, they said I should send it back to them so they can look again. seems like its them who has made it lose the data? they didn't have the ecu or keys, they just said to take cem of and post it to them.

As for sending it to a Volvo specialist they want so much per hour plus parts ect on top I just don't have the money(maybe if I had done that first I would have). which was why I was wondering if replacing the whole ecu/cem from another car would be an option?

Thank you, I really appreciate all your advice.

[Moose Test]

Replacing the CEM with another from a different vehicle is not possible. The configuration data it contains is specific to your car (including such things as mileage records and the key codes) and there are many software version dependencies between it and the other modules (of which there are MANY). Only a brand new CEM can have your configuration files restored to it (by reference to Volvo's own records).

Without wishing to sound like I'm lecturing you, yes, good specialists aren't cheap but there's a reason for that - they don't tend to take north of £500 from you and then hand you back a box of knackered parts and a non-operative vehicle. As someone once told me; There's always enough money to fix things twice. It's a painful lesson but you won't make the same mistake again.

Since you've already spent £500 on your CEM I would accept the offer of the original company to re-check it, so long as it's at their own expense, as it sounds as if you don't really have much to lose from that at this point. If it is viable, then you'll have already saved a lot of money vs a new CEM. If it isn't, well you paid them to repair it, so what are they going to do about it?

Whatever the outcome, try to recover what money you can (if appropriate)and seek out a professional diagnosis and repair from someone who is qualified to do so. Stop listening to people who are making costly guesses at your expense.

I hope it works out ok for you and that you continue to enjoy your '90

[XJSDriver]

Sound advice from Mouse Test - send your CEM back to be checked out and then take it from there. Let us know how you get on - good luck

[Sunnyday]

As I have not had a Volvo very long I am not sure this would work but I have had 2 simular cars that had all the same simptons as you are saying and on both cars it turned out some thing fairly simple.

It was the crank sensor! not saying this is what yours is but well worth a check

[galloot633]

Hannah
I can thoroughly recommend a garage in your area https://www.swiftest.co.uk/ my daughter discovered this place when she had problems with her audi a3, after several "specialists" in your area couldn't help her , I had to use them when my xc90 developed a fault on the way down and they sorted it no problem and they were very reasonable, they use the same diagnostic equipment as the volvo specialist in my area use, and they certainly know what they're doing
good luck Dave

[hannah93]

Thankyou all for your advice, the car is now FIXED!!!
my brother is the one who told me about replacing the ecu/cem he was so confident that it would work he went and got the parts, plugged them in and the car started. so happy to finally have my car back