Motor Control System Failure - Check your Battery

Originally Posted by mixy

FYI.

PS My battery was showing 12.9v and was working fine. Not that then... Oh, and my AC system now just blows out hot air after disconnecting my battery....wierd car! Any thoughts on this?

Mixy

Does it show that whilst cranking?

P

Ah, good point, i'll check that out, if it dips is this a problem? What is the tolerance?

I've had my 147 1.6L 3-door Lusso since new back in 2002 and had very few problems with it, until now (hence the reason I found this forum).

A fortnight ago I was in the Lake District on holiday, parked the car, put the tent up, went to move the car and it wouldn't start - turned over fine but it just wouldn't fire up. Left it 15 mins or so tried again and it started first time but with the Motor Control System Failure warning.
Next day it started first time, went for a drive, parked up while we had a dip in a tarn, got back to the car and it wouldn't start. A fantastically helpful local drove us round a few garages (all too busy to help) and then back to the car only for it to start first time... Same thing happened a couple of more times with the MCSF light being on sometimes and not others.

This situation has continued since we got back - seems to start fine when cold, but just won't up again when I get back to the car (turns over fine but won't fire up), MCSF light seems to be on permanantly now.

I don't know any decent independent mechanics in the Newcastle/Gateshead area so I was going to take it to the main dealer in Newcastle (who I haven't been impressed with in the past). Could anyone give me any pointers? I need a multi-meter to check the battery right?

Thanks in advance - this is a great pool of knowledge!

so is anyone prepared to come on here and say that changing the battery has fixed the problem long term? very mixed messages coming through..

Originally Posted by Joski

Hi

I've been reading this thread for some time, so I thought it was time to bite the bullet and buy a new battery. On changing the battery the VCD error I often got has disappeared for good (fingers crossed) however I'm still suffering the Motor Control System Failure.

This always occurs when I put my foot down in 3rd Gear; the car occasionally hesitates too during the sudden acceleration but then returns. I've also noticed that during harsh acceleration in 2nd gear the Motor Control System Failure doesn't light up but boy does the power drop, it feels like the engine is either getting flooded with fuel or not enough air is getting in. Is there anyone out there who has had a similar issue and managed to resolve it?

Oh and I forgot to mention, it's an Alfa 156 2.4 JTD 10v Veloce and the loss of power normally occurs around 2-3000rpm. The turbo sounds sweet and whines like it did the day I bought the car, so I think the turbo isn’t at fault as it does pull like a bat out of hell but this sudden loss of power has got me mystified. Could it be a sensor or something more serious?

Your help will be much appreciated.

I think I managed to sort it out. All it needed was a good blow

All I did was take the two small rubber hoses off what I think is the pressure sensor located above the radiator on the front of the engine bay. One of the hoses goes to the turbo and the other disappears under the engine cover. All I did was give them a good blowing. Then I tapped the sensor a few times and then as if by magic the MCSF warning has gone away. It pulls right through the rev range now with out a stutter.

I haven't got a clue what possessed me to do it, but I'm glad I did.

Hope it works for any of you lot who are suffering the same problem.

P.S. If blowing pipes and tapping the sensor doesn't work, I'd recommend you change the sensor as it's much cheaper than forking out a load of cash for a new / reconditioned turbo. My Alfa is getting to the 100,000 mile mark on the original turbo so if yours has a less miles on the clock, I'd investigate other avenues before shelling out for a turbo.

Originally Posted by realslimshady

so is anyone prepared to come on here and say that changing the battery has fixed the problem long term? very mixed messages coming through..

Didn't fix the problem for me - despite a new battery I'm still getting error messages.

SS

Didn't fix it for me either, my MCSF messages were due to a combination of turbo boost sensor, accelerator body and exhaust gas recirculation valve.

Every time one was changed the errors became a bit less frequent. They've stopped for 4 weeks now, fingers crossed!

Thanks for the story ! as I have said in many articles in the past, check the battery first ! if an electronic bugaboo starts appearing. This is not an Alfa issue , but for all makes of cars with ECU's and sensors (most all car makes nowadays !) batteries are the heart of the system.

Yeah, That is like for my Alfa also.

My alfa romeo 147 1.6 T.SPARK Lusso.

I received the EOBD - Motor Control System Failure warning notice as well.

The mechanic did a diagnostic check, and wrote down a list of what I needed to buy/replace:

He told me if I buy a water temperature sensor, air temperature sensor and lambda 2 signal (above cat) everything should work fine.

He also stated that I may reuire a new exhaust.

Originally Posted by ellzman

Yeah, That is like for my Alfa also.

My alfa romeo 147 1.6 T.SPARK Lusso.

I received the EOBD - Motor Control System Failure warning notice as well.

The mechanic did a diagnostic check, and wrote down a list of what I needed to buy/replace:

He told me if I buy a water temperature sensor, air temperature sensor and lambda 2 signal (above cat) everything should work fine.

He also stated that I may reuire a new exhaust.

good man that !! gets a lot of browny points selling kit ! did he advice a new flatscreen tele ?
funny that a new battery was not on the todo list... makes one wonder

rarebear was your post helpful or just waste?

Originally Posted by Dibby

Didn't fix it for me either, my MCSF messages were due to a combination of turbo boost sensor, accelerator body and exhaust gas recirculation valve.

Every time one was changed the errors became a bit less frequent. They've stopped for 4 weeks now, fingers crossed!

Well those are all now on my shopping list,as yes-battery replacement had no effect! Except for the c/c which now reappears more frequently than it did
It's in Tuesday so will ask for those items to be replaced,get the remap done,and see what happens...

I hope for help.....

Originally Posted by realslimshady

Well those are all now on my shopping list,as yes-battery replacement had no effect! Except for the c/c which now reappears more frequently than it did
It's in Tuesday so will ask for those items to be replaced,get the remap done,and see what happens...

I wouldn't go out and buy all that just yet, there's so many sensors, wires and conectors that could be causing your troubles.

I don't know if the 156 is the same but the 147 wipes its memory after a clear start-up and they can't read error codes off it if it's an intermittent fault and you restart the engine. Next time the error message pops up, take it straight to a garage and get the error code read without switching the engine off. Hopefully that will narrow it down to what's up on yours.

Originally Posted by Dibby

Didn't fix it for me either, my MCSF messages were due to a combination of turbo boost sensor, accelerator body and exhaust gas recirculation valve.

Every time one was changed the errors became a bit less frequent. They've stopped for 4 weeks now, fingers crossed!

Are you still fixed then Dibby?

Mine is at AHMotorsport now so we're going to start with the boost pressure switch and the associated tubing and see if that works-fault codes are all stored and it's showing boost and MAF (which is because I tried disconnecting it to see if it made any difference) do the 225bhp remap and generally have a fumble about. If I could eliminate the 'limp home' mode I'd just take the bulb out of the warning light and be happy
Update in 24 hours...

I'm still error free ... it's like being in drug rehab "Yes, I'm still clean" ... although I got an airbag warning light flash up for no reason - got to check the forums to see what that's all about.

Good luck with it, good news all the error codes were stored. Sounds like my plan too, get a remap done but first eliminate any errors and make sure the car's reliable before I go monkeying around in its brain

well, we didn't fix it.
changed the boost control switch and it was error-free all day, but as soon as i got it back and popped out onto the motorway..limp home.
so I'm going back to the (overhauled) turbo as the suspect-it hasn't been right since I fitted it and we're running out of things to point the finger at...trouble is the three day turnaround is somewhat inconvenient
oh, and if anyone has followed this thread from the start-battery change has not had ANY noticeable effect..

Bugger! Has it cut down the frequency of the errors? Every time I had something changed my errors would go from 3 times a day down to once a day, then to once every couple of days, then every week or so then the final bunch of work stopped it alltogether.

Keep going back and getting the error codes read is all I can say. Keep chasing the sources of the errors and you'll get there eventually. It's a pain in the arse having to keep taking it back, I feel or you dude, I was on the brink of asking for my money back but it's sorted and drives like a dream now.

trouble is, the error code is always the same-boost pressure.
have spoken to turbo people and we're going to try an adjustment-which means I'll remove it,adjust it on his say-so,and then of course refit it to see if it's had any effect. So that's a few hours of my day taken care of.
It's definitely weird tho-one minute it drops into limp just pulling gently away from the lights,yet earlier (about 2.30am in fact) had 135mph indicated no problem..
And cruise control still a law unto itself. Have ordered a brake light switch in the hope that might be the problem there. Onwards..
Keep me posted Dibby!

is your car a selespeed auto? I just wondered, as I had a weird set of faults similar to yours on an mr2 turbo auto, limp mode, ok when first cold start etc then weirdness sets in, no cruise, no overdrive, poor acceleration from rest (like its pulling away in 2nd) - it was pinking and the ecu was retarding the timing and couldnt correct it, still too weak a mixture so it went into limp mode. When cold enrichment was on, no problems at all.

I know yours is a diesel, maybe the fuelling is wrong because of injection timing, or fuel filter clogging. The symptoms can also be attributed to a wrong lambda reading, as it checks the unburnt fuel in the exhaust and adjusts the mixture accordingly. If it was reading rich, it would turn down the injection time and weaken the overall mixture - adaptive fuel trim. Boost obviously worsens any weak fuelling issues, maybe its a boost leak in the intercooler or pipes? Faulty BOV maybe?

Just suggestions of course but the battery issue, could be the fault for some folks cars as 12v is a low voltage, hence needs clean connections and good steady value for the cars ecu and sensors to work properly. A weak battery can indeed give funny behaviour from an ecu car, but its cheap and easy to try a new one to fix it first before expensive sensors.

Multiple sensor errors must stem from one common source. Its standard fault finding, that often seemingly unrelated faults are in fact, related in some way. Try to find the common elements, battery, fuse, wiring, earth points, positioning (a harness rubbing through can give several faults at onece, not related except the wires share the same path through the bodywork...)