for 9 months now I have been getting this code P2404 and MIL on. I have changed the LDP pump, fuel filter and Purge valve, and checked all the hoses and I still keep getting this code. No hose leaks detected. It will come on nad go off in a week or so and come back after few days and so on. Anyone has any ideas what could be causing this? Does anyone has evap/vacuum system diagram for audi a6 3.2l q 2005? I can only find 5v turbo online.

 

This is a leak detection pump sense circuit range/performance MIL. Check the vacuum hoses from the engine compartment to the pump for leaks and if the car is FWD, check the connection to the exhaust flap for a proper seal.

 

no hose leaks from engine to pump. What next?

 

A6 2006 Same code no good wiring diagrams found. Used scanner to activate LDP no signal to pump from pcm. Suspect open between pcm and ldp.
Pump tested good pin 1-3 670ohms. pin1-2 16 ohms.
customer needed the car so i was unable to continue my dignosis