A standard scan usually just checks for any fault codes,
And if they're "lazy" that's all they check.
A global scan is a specific test procedure where the scan tool checks EVERY module fitted with a chip and there's a few in that car.
They're interconnected via what is called the "CAN BUS" wiring.
And on some Fords the chipped components could be the engine ECU,
The ABS,doors,....................on and on.
Including the dash ECU.
I've had Fords in with canbus faults that actually stop the starter motor from working!
So from your description I'd say you have a faulty dash/speedo module,
Which would most likely show up in a global scan.
Or try contacting a specialist like "BBA REMAN".
Google them and follow their website to Ford dash faults.
You'll see your not alone.
Posted on Saturday 20th of August 2016Don't understand this? Ask a question