Fiesta Powertrain Warning Light

[BenK]

Hi All, hoping someone can help with an issue that has just developed on my 2016 Fiesta Black Edition 1.0 Ecoboost. I've just finished my drive home however halfway through I the 'spanner' Powertrain warning light came on and I immediately lost a tonne of power. 

I pulled over and checked everything I could think to check and can see no issue (no loose pipes/cables etc). 

The car has done 8500 with a J1 Induction Kit and custom cat back system without issue- the only recent addition to the car was a remap completed a couple of weeks ago. I've spoken with the company just and they are adamant the remap would not have caused this warning light to come on but I'm not sure what else it could be. 

I want to try everything before taking it back to the dealer to be charged £95 per hour to investigate, if I can rule out 90% of what it could be (or fix the issue myself) I'm hoping to avoid the cost. 

Cheers

Ben