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P1404 code?

Tiny
TABITHA6408
  • MEMBER
  • 2001 BUICK CENTURY
The "Service Engine Soon" indicator came on and stays on. I went to Advance Auto and they ran the machine on it. It came back with the code "P1404" and Emission Controls. What could this be and does it sound like a costly repair?
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Thursday, February 18th, 2010 AT 4:40 PM

5 Replies

Tiny
KEN L
  • MASTER CERTIFIED MECHANIC
  • 47,643 POSTS
This means the EGR are valve is not working or stuck closed. here is a video that will help you test it with the valve location in the diagrams below:

https://youtu.be/DqUCbbKdWf4

Check out the diagrams (below). Please let us know if you need anything else to get the problem fixed.
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Sunday, December 13th, 2020 AT 1:13 PM
Tiny
GWHITLEY89
  • MEMBER
  • 2 POSTS
  • 2001 BUICK CENTURY
  • 3.1L
  • V6
  • 2WD
  • AUTOMATIC
  • 150,000 MILES
I have the car listed above custom model. I have a famous p1404 code of course I replaced the EGR valve and EGR tube and cleaned out the airway between EGR valve and throttle body. Code still comes back after being cleared! My question is, would a bad PCM make the computer throw that code? This happened a year ago too but when I changed the EGR and EGR tube it went away for a year and then cam back on that when I cleaned out the passage way. So I just replaced the EGR valve for the second time thinking it went back but clearly not the issue. I have no other issues with the car just p1404 code.
Any info helps. Please and thank you.
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Sunday, December 13th, 2020 AT 1:13 PM (Merged)
Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 109,755 POSTS
Hi,

The most common cause of this code is exactly what you described. However, other things can cause it. Here is a description of the code and how it correlates with the PCM:

The Power-train Control Module (PCM) monitors the Exhaust Gas Re-circulation (EGR) valve pintle position input to ensure that the valve responds properly to commands from the PCM. When the ignition switch is turned ON, the PCM learns the EGR learned minimum position. The PCM compares the EGR learned minimum position to the EGR position sensor when the EGR valve is commanded closed. If the EGR position sensor indicates that the EGR valve is still open when the PCM is commanding the EGR valve closed, this DTC will set.

Since you already replaced the EGR and there are no carbon issues, that leads to testing. I have attached two pics below which are basically a diagnostic flow chart for determining the cause of the problem. Take a look through them and see if anything helps.

Let me know.

Joe
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Sunday, December 13th, 2020 AT 1:13 PM (Merged)
Tiny
GWHITLEY89
  • MEMBER
  • 2 POSTS
Okay, I have one more question on the throttle body. There are two cables a throttle body cable and a return cable to the PCM which is broken could this cause the PCM not reading the way it should and make it throw that code? Due to it not positioning that cable?
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Sunday, December 13th, 2020 AT 1:13 PM (Merged)
Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 109,755 POSTS
Hi,

Honestly, anything is possible, but I don't see a direct correlation. Can you do me a favor? Take a picture of the cables you are referring to and upload them for me to see.

I will watch for your reply,

Joe
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Sunday, December 13th, 2020 AT 1:13 PM (Merged)

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