Error code p0411

2005 BUICK LA CROSSE
8,000 MILES • 3.6L • 2WD • AUTOMATIC
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JD77
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I have replaced plugs was thinking of o2 sensor eliminator. But I don't know.
Jan 28, 2021 at 10:56 AM
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ASEMASTER6371
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Good afternoon,

I am sorry, there is no 411 code for your car. Can you verify the code so we can help you?

I looked for other variations of the 400 and found nothing.

https://www.2carpros.com/articles/checking-a-service-engine-soon-or-check-engine-light-on-or-flashing

Roy
Jan 28, 2021 at 12:02 PM
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SEVAG P
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Hello,

Fault code p0411 is related to secondary air injection system, it has a long diagnostic steps.

open under hood fuse box check below figure 1,2,3,check the emission fuse 12 which is 10A,also fuse 25 which is 50A air injection pump relay.

check our guide below how to check fuse.

https://www.2carpros.com/articles/how-a-car-fuse-works

When the fuses are in good condition, check scan tool activate drive link on/off air injection pump if its working. if not check the pump relay which is located on the left front rail rear of bumper support, when the relay and the supply voltage good then air injection pump defected.

check our link below how to check relay

https://www.2carpros.com/articles/how-to-check-an-electrical-relay-and-wiring-control-circuit

When the pump activates then we have clogged air passages or leaking from a defected hose.

Let us know what happens with you.

Thank you.
Jan 28, 2021 at 12:29 PM
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STEVE W.
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That code is common on the cars with the air pump mounted low. They get some moisture in them and the motor seizes up. Another common issue is the check valve assembly on them seizing up because of the way they operate. One side has exhaust in it and the other side outside air. The heat makes them fail.
Nothing to do with ignition or O2 sensors. Oh and FYI any type of "eliminator" will just turn on the CEL and cause poor engine performance.
Jan 28, 2021 at 1:04 PM