PO401 EGR VACUUM HARNESS 6L2Z-9E498-A

[jbwilli]

I am chasing a PO401 EGR Code. I suspect the black plastic vacuum line to the EGR may be clogged, broken/etc. The pn 6L2Z-9E498-A VACUUM harness has 3 black and 1 red hard plastic vacuums line within in. The large end of this harness connects to the top of intake where it gets it's vacuum source. All 4 of the lines end in that intake connector. One of the black lines runs inside the harness all the way to the one-way check valve on the firewall behind the EGR that controls a blend door. Another paired black and red line run inside the harness all the way to the EGR where they end into a rubber 2 port but one-piece vacuum elbow connector to the EGR. The final and 4th line is black and from pics of the harness, it appears to run inside the harness and under the intake where it terminates into a one port rubber elbow connector under the intake. This line does not run inside the harness all the wy to the EGR, bu tonly half way to the connection under the intake. I disconnected the harness at the large end at the intake connection and plugged it off. Behin the EGR, I disconnected the single black line to blend door AND the rubber elbow connector to the EGR. I pulled a vacuum on all 3 of these lines individually. The black line to the blend door and the red line to the EGR held vacuum. The black line to the EGR would not hold a vacuum. 1) is that normal. I cannot access the 4th black vacuum line connects under the intake to perform a vacuum test on it! This harness and where the 4 lines run inside of it have me confused. Any help or comments would be appreciated. I ordered a new one. When it gets here, hopefully I can figure it out! THANKS!

 

[jbwilli]

I am chasing a PO401 EGR Code. I suspect the black plastic vacuum line to the EGR may be clogged, broken/etc. The pn 6L2Z-9E498-A VACUUM harness has 3 black and 1 red hard plastic vacuums line within in. The large end of this harness connects to the top of intake where it gets it's vacuum source. All 4 of the lines end in that intake connector. One of the black lines runs inside the harness all the way to the one-way check valve on the firewall behind the EGR that controls a blend door. Another paired black and red line run inside the harness all the way to the EGR where they end into a rubber 2 port but one-piece vacuum elbow connector to the EGR. The final and 4th line is black and from pics of the harness, it appears to run inside the harness and under the intake where it terminates into a one port rubber elbow connector under the intake. This line does not run inside the harness all the wy to the EGR, bu tonly half way to the connection under the intake. I disconnected the harness at the large end at the intake connection and plugged it off. Behin the EGR, I disconnected the single black line to blend door AND the rubber elbow connector to the EGR. I pulled a vacuum on all 3 of these lines individually. The black line to the blend door and the red line to the EGR held vacuum. The black line to the EGR would not hold a vacuum. 1) is that normal. I cannot access the 4th black vacuum line connects under the intake to perform a vacuum test on it! This harness and where the 4 lines run inside of it have me confused. Any help or comments would be appreciated. I ordered a new one. When it gets here, hopefully I can figure it out! THANKS!

*** UPDATE *** I found the black line at the 90 degree 2 port rubber connector (red & black) at the EGR broken close to the connector, but hidden under the spiral wrap! SURPRISE!: This black line DOES NOT go into the straight 2 port rubber connector (red & black) on the opposite end of this harness at the intake! Instead, it goes into the connector head, paired with the other black line (goes to HVAC blend doors. The black line paired with red line at the intake end in the 2 port rubber connector, connects to the Fuel Pressure Sensor located just under the front of the intake on the right fuel rail! In other words, the black line (paired with the red line) in the rubber 2 port connectors at each end of the harness ARE NOT the same black line! It is true, that all 4 lines are common to each other between the ends and a leak or crack in one, will affect all 4! The HVAC blend door black line has a one way check valve in it, to prevent any break/leak PAST the check valve from having any affect on the EGR vacuum loop. Hope this helps!

 

[Blackhawkxx]

Thanks for the info and update. I'm sure it will help someone down the road.