P0401 Cadillac -

Question

Changed egr valve in my 97 Deville. Changed o2 sensors pre cat and after cat. Now I get a check engine light code p0401. Any ideas to solve this problem? Need to get car smogged.

Answer 1

P0401 EGR flow insufficient flow detected

When the CK ENG LT comes on especially for P0401

The EGR port and tube is plugged. To solve this remove the EGR use a coat hanger or wire and unplugged the port

Here the EGR tube  removed this vehicle had a P0401  which is unsufficient EGR flow, the fix unplugged the carbon build up.