P0491 Secondary Air Injection System Insufficient Flow. Stumped

Question

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

Replaced the Secondary Air Pump
Replaced the Combination Valve (did not replace the metal gasket)
Replaced the O rings
Replaced the pressure sensor
Replaced engine air filter
Checked for leaks
Checked to see if the exhaust hole in the manifold was clogged
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

Air Pump

Air Intake

OBD11 Idle

OBD11 Basic Settings Test Results

Old_Fossil · Answer

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.

Answered by Old_Fossil on December 19, 2020

P0491 Secondary Air Injection System Insufficient Flow. Stumped

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