No throttle response

[hoggster]

Audi A4 2002 2.5 TDi starts as normal but when try to accelerate esp light comes on and will not accelerate at all. engine stays at idle speed. start again all lights out until you touch accelerator pedal. Have tried new pedal potentiometer - no difference. Can anyone advise please.

[bez101]

Audi A4 2002 2.5 TDi starts as normal but when try to accelerate esp light comes on and will not accelerate at all. engine stays at idle speed. start again all lights out until you touch accelerator pedal. Have tried new pedal potentiometer - no difference. Can anyone advise please.
scan it for codes