Cuttingout/diagostics says no fault

Ive plugged  a diagnostics on the car and its showing no faults but it keeps cutting out at 10-20mph. Any ideas

I see you have another thread with the same issue, it's probably best to keep updating one thread rather than starting a new one, otherwise anyone reading it doesn't know what you have already tried.


Unfortunately I don't have an auto so don't know if this is something specific to the auto gearbox, but here goes.

Q) What sort of RPM is the vehicle doing when it cuts out? I know the speed is between 10-20mph, but RPM is more important to understanding what is happening.

Q) When the engine dies, does it misfire first or stutter or does it just die?

Q) If it just dies do you get the 'Padlock' immoblisier symbol on the dash?

Q) How old is the car, what is the mileage and when was it last serviced?

Possible causes
There are a large number of causes of engine stalling at low revs (assuming the revs are low), but basically it's either fuel or spark.

Spark
You need a spark at the right time to ignite the fuel.  As the revs drop the spark is usually not quite as strong so things to check are

Spark plugs - Are they clean and in good condition?
Leads/Plug Caps - Are they clean and free from breakages/cracks?
Battery - Is the battery in good condition and well charged?

After that it's timing, but that gets harder to check, it could be the CAM/Crank position sensor.

Fuel
This is the longer list, some of which are harder to check.

Fuel - Is is clean, or dirty, any water in the tank?  Is the fuel pump OK?  Fuel filter and injectors clean and working?  What about fuel pressure?
Air Idle Control/slide - Is this clean and working?
EGR Valve - Is this working correctly?
Air filter - Unlikely to be only at low revs, but is it clogged?
Faulty O2 sensor - This should show up in the fault code, so probably not the problem

Auto-gearbox
It could also be a fault in the gearbox, if the gearbox is not changing down and the revs drop very low (say less than 1,000 - 1,500 rpm) the engine might just cut out under load.  I don't know enough about the greabox to know if this is an issue.

Robin
 

Doesn’t miss fire
07 reg
Revs are about 1000
Done 66k mileage
Ive noticed the orange engine light sometimes shows
No padlock light
Many thanks

The orange light is probably the 'Check Engine Light', it comes on when you get a misfire or a stall.

If there is no 'Padlock' then we can rule out the immobiliser.

I don't know enough about the auto gearbox, but I would have thought that 1,000 rpm is too low to pull at 10-20mph, my old manual Gen 3 would have probably cut out at 1,000 rpm trying to pull at 10-20mph.

Certainly it sounds like the gearbox is sticking in too high a gear and is not changing down, hopefully someone with an auto can jump in and confirm if this is normal behaviour or if there is an issue with the gearbox?

Robin

If it cuts out and doesn't set a code, then the ECU thinks that the engine has stalled, and Everything is OK really.

Usual suspect is the crank sensor, when it gets old and hot and bothered it can't be bothered outputting a signal, so everything stops as the ECU thinks the engine isn't going round.