ESP/Traction control light

[Shandyman10]

I have an intermittent fault with my MK7 where the ESP light comes on and the van lacks power, max 2-2.5k revs.
Turn ignition off and back on, resets and away we go.
This has happened many times, but at completely random times and over long periods of time.
It has been plugged in several times by different garages including Fords at Chandlers Ford Southampton but it doesn't seem to save any fault codes.
Fords advised to bring the van in with the light on so they can plug it in with it on, but this easier said than done as it never comes on anywhere close to them.
it came on again today so I went and spoke to Fords and the workshop manager said it's unlikely to be the ESP or brake related as the engine looses power so must be engine related.
Plus I'm not convinced they will find anything as last time they plugged it in they found nothing and charged about £120 for the privilege.
Does any one have any idea what could cause this fault?
Im also thinking of getting a code reader to carry in the van, so I'm looking for recommendations as to what to get.

[knobby1]

Im also thinking of getting a code reader to carry in the van, so I'm looking for recommendations as to what to get.

Forscan (free to download the PC version)....and a 15quid ELM-327 and you be sorted.

Lord Knobrot

[Airthies]

I'd be checking the stator rings and sensors are close enough and not contaminated.
If one was broken it'd more likely throw a malfunction light.
It sounds like its loosing pickup on one wheel or other. So thinking it's going into a skid.

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