From Ross-Tech Wiki

17705/P1297/004759 - Pressure Drop between Turbo and Throttle Valve (check D.V.!)

Possible Symptoms

  • Malfunction Indicator Light (MIL) ON
  • Power Loss

Possible Causes

  • Leaking Hoses and/or Pipes between Components
  • Turbocharger Recirculating Valve (N249) (Diverter Valve) faulty
  • Throttle Body dirty
  • Vacuum leak
  • Boost Pressure Control Valve (N75) faulty

Possible Solutions

  • Check Hoses and Pipes between Components
  • Check / Replace Turbocharger Recirculating Valve (N249) (Diverter Valve)
  • Check / Clean Throttle Body
  • Check for Vacuum leak(s) including PCV system
  • Check / Replace Boost Pressure Control Valve (N75)

Special Notes

  • When found in the NAR 2.0T (BPY) check RVUTB: 01-09-03 or 2018919 for updated Crankcase Breather Valve
    • If the breather valve is faulty, full engine vacuum is typically found when removing the oil cap at idle.
  • When found in 1.8T engines, such as the (3B) B5/B5.5 Passat, check the PCV "bleeder valve". Example part number 06B-103-245
    • One way to troubleshoot the problem is to pinch closed the vacuum supply hose that attaches to the bleeder valve to see if the excessive crankcase vacuum is resolve resulting in a smooth idle.