CEM clean now PS (EPS) pump on all the time

[supafly]

On the line of investigating the alternator I found this...

From https://www.volvoforums.org.uk/archi.../t-219325.html

by - KBB

"The reason I ask about the time between your alternator failures is I have over the years seen a number of alternators changed and the replacement alternator fail again in a couple of months and some within a week if it has been a daily all day driver. Often the replacement alternator has been accused of being faulty or a sub standard replacement and on readdressing the occurring problem a 3rd alternator is fitted and for good measure a new battery just in case it was damaged during the malfunctioning alternator and the all is well.

Often on forums when a poster reports an alternator producing 15v at idle speed they will receive recommendations’ that the alternator is the problem and must be changed, this is not necessarily correct. An alternator at engine idle speed will not even be capable of producing half of its charging capacity and if all electrical loads were turned on at idle the charging system would not meet the total electrical demand. Charging systems can only be accurately assessed at 2000 RPM.

Above where I made mention to successive failing alternators the cause of the alternators failures were down to the battery. The batteries in question had no problems in starting the vehicles and had also passed a “midtronics” battery test and a load test, the problem is a high internal resistance in the battery causing the alternator to max out and then damage the rectification diodes. Batteries require more voltage to charge when they age and also when they are cold, temps below 5deg will raise the internal resistance of the battery a combination of an ageing sulphating battery and a low ambient temperature will increase the batteries internal resistance significantly which will force the alternator to increase voltage output to push the charge through the battery 15v being the max rating.

The most accurate test requires a DC inductive current clamp, connect it around the battery ground cable, if the battery has 2 or 3 ground wires off the post then you must place the jaws of the clamp around them all, start the engine and let it idle expect initially to see 20amps of inrush current and let the engine run for 10 minutes. After 10 mins the residual charging current through the battery should drop below 10 amps the norm is 6-4amps (same rate as bench top battery chargers). If after 10 mins the residual current is above 10 amps then the battery is suffering from high internal resistance and must be replaced. It is this unchecked fault which goes on to destroy the alternator.

The next potential problem to test for is a failed or leaking rectifying diode that leaks AC voltage onto the DC system, early onset can be flickering lights at idle speed and bad cases of creating false sensor inputs. I have seen auto transmissions shift when they should not, engines misfire, ignition events totally out of sequence and ABS activation for no good reason. To test set DVM to AC mili volts connect red to alternator power stud and black to alternator case, raise engine speed to 2000 RPM and note the reading which should be below 150mv above that is an indication of the diode starting to leak. The problem I mentioned above had 400mv AC the auto trans issue has a leakage of 700mv AC."


I've yet to do these checks. I'll be checking the connector first then I'll do the alternator checks and post back.

[supafly]

Does anyone know what actually fails on the CEM?

I see that people swap them out after having the data transferred between the old and 'new' one. With the amount of failures I am reading about across different models has anyone ever looked into the root cause rather than just replacing the part?

I found one thread where the CEM has been disassembled (with pictures) to understand how to make changes to it, but they didn't attempt to address any potential failure points.

If my above checks aren't successful I'll be taking it apart to check for any damaged tracks or bad joints. I won't be splitting the boards so I will only be able to check what is visible on the surface. I'm hoping if it is a dodgy CEM that it might be something obvious...

[supafly]

Unfortunately I had no joy when taking it apart, I couldn't see anything obvious. I obviously only had access to the top and bottom of it and I didn't fancy trying the separate the two boards.

I haven't touched the car since...

[supafly]

The CEM is going to be sent off to https://bba-remanshop.com/gb/ for them to check and repair. I'm hoping this will be the end of this saga...???

[LizardOfBodom]

Originally Posted by supafly

The CEM is going to be sent off to https://bba-remanshop.com/gb/ for them to check and repair. I'm hoping this will be the end of this saga...???

fingers crossed! How much it will cost you just for the service?

[emy]

Originally Posted by supafly

The CEM is going to be sent off to https://bba-remanshop.com/gb/ for them to check and repair. I'm hoping this will be the end of this saga...???

It is really frustrating having so many faulty warnings and yet do not find out the root cause of them.
I also had many warnings, (brake failure stop safely, anti skid, Acceleration pedal, wipers/indicators will not stop unless stop the car....) but none of them were so serious to make the car undrivable. The location of the CEM is OK, but the location of the pollen filter is bad, every service the CEM has to be moved or removed to access it, mechanics do not handle it properly, just pulling, pushing all the cables to rich the pollen filter.
I took it out cleaned it, there was dust, not much but still, with this occasion I change the pollen filter too without removing the CEM bracket....nightmare..
Its been a month since and none of the faulty messages came back. I hope it will stay this way...
Look at the picture, they broke the connector clip and improvised with a cable tie which I have to replace it every time I disconnect it.
One person said....if you want to keep your car longer and problem-free, look after it yourself, do not give the keys to the mechanics, the less visits to the garage the better...

[supafly]

I was going to use Lukas who I found from the forums, he quoted £260 but then didn't follow up on our conversation where he said he would send me the address and details to post the unit to.

I then contacted BBA Reman who said £159. I've been so fed up with the car that I haven't even been to take the CEM out of it. I did read some shockingly bad reviews on trust pilot about them but the google feedback seems to be a mixed bag. Right now I'm out of options so it will be going to BBA and I hope I have a good experience with them, which I will follow up with a review.

I've done all of the work myself on the car with the exception of the clutch and flywheel. Which was due to time issues. Sadly I'm almost always disappointed by work I've paid to have done, the clutch is another point, when I was checking the looms earlier in this thread, I found that they had not clipped the wiring into place correctly, a simple fix, but one that shows they just rushed the job of putting it back together.

I've been very careful when changing the pollen filter and I have found in my experience that I need to change it every year.

I can understand if water got into it or there was a short somewhere but when I took it apart I couldn't see any traces of that. I'm fairly confident with electronics too and was hoping it would be something obvious but I can't see anything obvious. It would be nice to know what actually fails on these.

I debated getting a vida dice set up but even that is going to cost me at minimum north of £100, so rebuild looks to be the most cost effective at the moment??? (assuming that it is the cem at fault)

[andy_d]

with a car as complex as the v50 platform
not getting a dice/vida setup leaves you "hope its that", guessing and costing you £ on "oh its not that" and getting flustrated

Vida/dice will pinpoint Which module it is and Then give you the how to get to it, what to do to fix it steps.
its More than just diagnostics, its a Full dealer level workshop manual with "how to", part numbers, parts diagrams, And diagnostics.

you can if you wish view "live data" when needed,


what Fails on the CEM is the connectors, both on the cable ends And the CEM itself, due in some cases to water , being kicked by passengers feet, being wrenched about by "mechanix" when changing the pollen filter,
IF the sunroof drains are maintained properly after the silly boot ends are attended to, then water isnt an issue, IF the pollen filter is changed and Care is taken with the cem,AND the proper procedures followed when it is disconnected (listed in vida , step by step) then there usually isnt many issues Unless passengers kick them,,,

[supafly]

Thanks for taking the time to post Andy.

You are spot on about getting frustrated. I've been there far too many times with this car unfortunately.

I suppose the crunch point for me is that if I commit to buying a vida dice set up (£110 + windows 7 pro upgrade + new battery for decrepit laptop and several hours getting it all set up correctly) I am in essence committing to stay with the car or Volvo's for that matter. When you're this fed up with something it becomes difficult (even though it is a very logical step).

However, you are right. Thank you for pointing out the correct logical way of approaching this. I've got a laptop with windows 7 home edition, so I just need to pull my finger out, upgrade and order the vida dice.

[andy_d]

Been there with previous volvo's
had the haynes manwells of lies
have 40years exp working on cars + motorbikes
"AGGGHHHH" car says "NO" "look car i replaced that bit,, turn the sodding light out its FINE,,, " and the car Still puts the light on "ok ok ill tell you its been fixed",, "oh look the f*** lights off now",,
my S40, a mate very kindly got it valeted for me as a bday pressie ,,, said valets knocked or moved or disturbed the cables for the side air bags srs light = on,, ended up having to goto a dealer to get it turned off,, when i had saved up enough to get some leather seats to replace the ripped cloth povery spec ones i got a dice unit, so leather seats got fitted,, and the seller had lied the passenger airbag was deployed. Dice costs paid for then and there,, fault found, airbag from cloth seat fitted, srs system checked + cleared - in profit on the dice unit, Then i fitted heater elements to the seat, changed the a/c + seat heating controls = quids in with the dice costs.

The thing with "committing" to volvo,, yes and no.
you may find with the ease of "aha so its THAT" that dice brings to the table your Happy to stay with volvo's , and if your not "for sale , dice unit fully tested" post on here and your not that out of pocket.