Engine cut off while driving
 

Hello. I am facing the problem when engine has a series of cut offs while driving. These cut offs happens just for a part of a second and is not a pleasant surprise. I have noticed that it happens when engine is warmed up and when driving in speeds under 60 mph. It happened few times at 70 mph, but it have never happen at 80 mph. Sometimes it happens just 10 miles after start and sometimes does not happen in 400 miles. ECU does not show any faults.
This problem does not appear on exact conditions, so it is difficult to understand what could be wrong. I am wondering if someone have had the same problem and could help me out?

I had luck to record it, so you can see it in the following shortcut (ignore engine fault on the dash, because it has already been fixed, but the problem persist):
https://www.youtube.com/watch?v=0pWb_BtQDCE

Thank you in advance!

The way those warning lights are flickering I’m thinking CEM issue. Do you have a sunroof? I’m thinking water ingress into the CEM which generally causes all kinds of gremlins.

TT

Hi
If not CEM
Alternator on the way out???


Iain

Hi
If not CEM
Alternator on the way out???
Or poor connection on battery/ alternator??

Iain

Thank you for the answers.

The Thong,
There is no sunroof in the car. Do you think that there could be an oxidation on connectors or faulty CEM unit? Do you know where is it located?

IainG,
I suppose if there is fault in alternator, the voltage still could be supplied form the battery and otherwise. Is there a possibility that faulty alternator cuts off the engine even if the battery is OK?

The CEM is under the glove box in the passengers side right where they can get kicked. I believe the pollen filter is near it too that has a potential to cause corrosion in the pins in the box. Look on YouTube , there’s plenty of info pertaining to them and the issues with em. Luckily I’ve never had that issue but it seems plenty have, good hunting.

What diagnostic equipment did you use to check for faults?

TT

Hi

On mine the alternator had a short and it was enough to drop the battery voltage to cause loads of faults including loss of power steering and then finally engine shut down.

Prior to the failure I had a few intermittent faults that then cleared.

If there is an intermittent fault or connection it could cause errors and faults that then reset when the voltage rises again.
Just a possibility as are the CEM connections.
Volvos seem very vulnerable to low or intermittent battery or circuit voltages.
Iain

I’d go with that too, the V50’s are sensitive to voltage drops. Certainly worth checking out.

TT

Thank you for your help, I have finally found the issue. The problem was a loose connector on the crankshaft position sensor, when I touched it, engine stopped. I did not expect that this kind of problem can be related with engine temperature, but anyway, happy to trust the car again.

I appreciate your help!

Hi
Excellent.
Nice easy fix.
Glad you have posted the "Fix" could be very useful to others

Iain