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Check engine light on and codes PO404 and PO403

Tiny
MARIA TOBBEN
  • MEMBER
  • 2000 PONTIAC GRAND AM
  • 3.4L
  • 6 CYL
  • 2WD
  • AUTOMATIC
  • 160,000 MILES
Po 404 po 403 codes replaced the EGR valve EGR solenoid PCV valve and cleaned out the intake port. Check engine light still comes back on and I can't get it to pass emissions. Cleared the codes as well.
Friday, August 7th, 2020 AT 7:26 PM

4 Replies

Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 108,336 POSTS
Hi,
The codes are both related to the EGR and deal with an electrical issue (low voltage). Do you have access to a live data scan tool? It is needed if I provide the diagnostics related to the codes. If not, the best we can do is check the connections at the PCM.

I attached a schematic below and highlighted the connector colors. The PCM is located below the left side of the instrument panel near the steering column.

Make sure the battery is disconnected prior to disconnecting the PCM connections, and reconnect the PCM before you reconnect the battery.

Pic 2 shows the PCM and how it's oriented under the dash.

Let me know what you find.

Take care,
Joe
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Friday, August 7th, 2020 AT 9:48 PM
Tiny
MARIA TOBBEN
  • MEMBER
  • 3 POSTS
Okay, thank you so much for your time. Gonna say that later and I will let you know how it goes again. Thank you.
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Saturday, August 8th, 2020 AT 1:18 AM
Tiny
MARIA TOBBEN
  • MEMBER
  • 3 POSTS
Yes, I have a code reader that has live data.
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Saturday, August 8th, 2020 AT 11:46 AM
Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 108,336 POSTS
Hi,

If possible, can you let me know what the short term fuel trims are? I'm want to see if there is a vacuum issue with the EGR.

Let me know.
Joe
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Saturday, August 8th, 2020 AT 9:20 PM

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