My VW CC 2010 is having a CEL with the code P0491 which means the pressure sensor is not detecting enough air being pumped from the intake into the exhaust. No other codes. No problems since this is only used for emissions purposes.

I have already

  1. Replaced the Secondary Air Pump
  2. Replaced the Combination Valve (did not replace the metal gasket)
  3. Replaced the O rings
  4. Replaced the pressure sensor
  5. Replaced engine air filter
  6. Checked for leaks
  7. Checked to see if the exhaust hole in the manifold was clogged
  8. Checked to see if the relay was opening and closing the combi valve correctly.
Full car details
Year: 2010
Make: VW
Model: CC
Engine: 2.0L TSI CBFA

Combi Valve Combi Valve

Air Pump Air Pump

Air Intake Air Intake

OBD11 Idle OBD11 Idle

OBD11 Basic Settings Test Results OBD11 Test Results

1 Answer 1


P0491 Possible Causes: Intake leak, damaged Air system components, faulty Air system solenoid or relay. The metal gasket could be the source of a leak. You can also visually inspect the associated wiring for cracking, corrosion around the contact pins and plugs. When I owned a VW years ago it was notorious for electrical issues. If you have a helper sitting the drivers seat watching the instrument cluster while you are moving the wires gently one by one. He will advise when the reading change on your OB2 code scanner or the CIL goes out.

You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .