I have a 2007 Fabia diesel, the engine management light has come on, the red/lilac wire to the electrical unit under the bonnet has low voltage and I am getting ‘P2100’ fault code, ideas pease ?

 

P2100 is a generic fault code indicating an issue with the throttle body, since you have a diesel with no throttle body this is clearly not helpful.

Please tell us the symptoms you are experiencing and which engine you have.

A 2007 model will have a throttle body, part of Euro4 emissions. Not connected to the pedal in anyway but is still called a throttle body.

Check continuity of the red/lilac wire to engine ECU pin 75, and the red/blue wire to ECU pin 81.

Then check that the brown wire has continuity to earth/battery negative; and that the blue/black wire has 12v with ignition on.

 

Ok, it's the anti shudder/runaway valve thingy, I hate generic OBD codes, they're so unhelpful, like throwing a dart blindfolded.

If it's not the wiring then it's the valve itself that's faulty.

I had this on mine 1.4 td at around 90,000 km. There was a (2?) plastic cog(s) inside when you split the body that had a couple of worn teeth.

I spent a week on the web cross referencing part numbers to source a replacement part from the original suppliers (valeo?) for half the dealer price just doesn't have vw/Audi stamped into it. 

Strangely, the replacement part is still going strong some 240,000km later, which leads me to believe their must have been a few dodgy ones that made it to the line.

19 hours ago, sepulchrave said:

Ok, it's the anti shudder/runaway valve thingy, I hate generic OBD codes, they're so unhelpful, like throwing a dart blindfolded.

If it's not the wiring then it's the valve itself that's faulty.

 

Yeah they are unhelpful. But then Skoda do still call it a throttle valve anyway as it’s the same part be it petrol or diesel and from an ECU control point of view works the same way.