Peace & blessings. My ford focus vignale 2L automatic diesel EcoBlue suddenly slow down with a jerk on reduced speed, like when you approach a traffic light or stopping the car. It's for the Last one week. I had a message - service engine soon which disappeared after long drive because it was driven on short distances for 2 months only on weekends. 

The problem I noticed after the service engine soon warning disappeared only when the gear is shifting down on slowing the speed. 

Any idea, what's wrong here? 

Many thanks in advance! 

Hi,

As the car has only done short journeys, the first suspect here is low battery charge.  If you can plug in a mains charger overnight to top up the battery, that is the cheapest option to try first.

If the warning has disappeared then it sounds like the fault warning (service engine now), not the service reminder warning.  The fault code triggered at the same time as this warning can only be read by Ford diagnostics.  I don't know whether you'll have a Ford dealership on IOM, so getting Forscan yourself would be the only way to read that code.  Given the low mileage I would expect it to be caused by either low battery charge or by the DPF filling up without being able to complete a regeneration cycle.

Or the wet belt breaking up, the car is 6 years old now

17 hours ago, Neb_engineer said:

Or the wet belt breaking up, the car is 6 years old now

Yes, possibly.

How many miles has this car done?

How often has the oil been changed?

What king of driving are you doing in it?

And yes, probably needs a battery too.

But get the belts changed

8 hours ago, DaveT70 said:

Yes, possibly.

How many miles has this car done?

How often has the oil been changed?

What king of driving are you doing in it?

And yes, probably needs a battery too.

But get the belts changed

50,000 miles, regularly serviced. Short runs in a town. Getting a recall

Update tomorrow.

Will this update fix the issue?

"Powertrain control module pcm software update

Campaign/NHTSA#

24S33/24V330

Issue Date

2024-05-14"

Possibly, possibly not.

14 hours ago, Tofail said:

Short runs in a town

This is really not ideal for this engine, if you are not fully "regenning" the DPF you will get oil dilution from the excess diesel put in to perform a regen.

I would strongly recommend getting the wet belts done

And then, as you do short journeys, change the oil every 5,000 miles

oh, and deactivate stop/start