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Service engine light. Code reads p40601 EGR insufficient…

Customer Question
Service engine light....

Service engine light. Code reads p40601 EGR insufficient flow. Cleaned old EGR, reset code. Light came back on. Cleaned EGR again, reset code. Light came back on again. Replaced EGR Valve, reset code. Light is back on. What is the next step?

Mechanic's Assistant: Have you seen this code before? Have you tried a hard reset?

I have not. I am not sure how to do a hard reset.

Mechanic's Assistant: What is the make/model/year of your car?

04 Buick century

Mechanic's Assistant: Are you fixing your Century yourself? What have you tried so far?

I am. Cleaned EGR valve and passageways. When the light came back on after 2 attempts to clean, I replaced the EGR valve.

Submitted: 4 months ago.Category: Car
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Answered in 1 minute by:
3/18/2018
Auto Mechanic: Ron, ASE Certified Technician replied 4 months ago
Ron
Ron, ASE Certified Technician
Category: Car
Satisfied Customers: 38,628
Experience: ASE Certified Tech
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Hello. My name is ***** ***** I am happy to assist you today. Give me just a moment to review your post, and I'll be right back with the help you need.

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Auto Mechanic: Ron, ASE Certified Technician replied 4 months ago

The code you have listed is not a valid Buick code. Are you sure the code Is not P0401?

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Customer reply replied 4 months ago
Sorry right that is the correct code p 0 4 0 1
Auto Mechanic: Ron, ASE Certified Technician replied 4 months ago

Okay, thank you for that information, the common cause for the code P0401 to set on your 2004 Buick is not usually a failing EGR valve but usually due to carbon build up in the EGR Passages which will cause low EGR flow. What you are going to want to do is give the EGR passages a good cleaning and in most cases that will solve this problem and code as well. I have enclosed the steps to clean the passages in the link below. Follow them exactly as written.

https://www.dropbox.com/s/ajcz3gl5cxo9knw/EGR%20passage%20cleaning%20Mar%2018.pdf?dl=0

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