DTC P0430 and P0420?

2015 CADILLAC SRX
84,000 MILES • 3.6L • V6 • 2WD • AUTOMATIC
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[email protected]
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Hi.

My CEL went on...day after an exhaust leak started...
As I Cannot do my own work anymore. I went to a Mechanic....
But I had scanned and had 0430 before that...
He advised me to replace convertors ..
Which I did...aftermarket.
When I picked up the car.... no cel
But within 6 miles it went on..
So I scanned..and found 0420 in additio to 0430...
Then I found out about drive cycles..
I was able to get the Ready Test to all green......Ready..
But Cel was still on...
Do You think I should Repeat drive cycle....with more miles and start stops...with overnights..
Thanks
Sep 11, 2024 at 3:07 PM
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JACOBANDNICKOLAS
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Hi,

If the monitors are complete, the light should be off. You may have to clear the codes and start over again with the drive cycles.

As far as the problem, where is the exhaust leak located? If it is upstream from the catalytic converters, it can cause a lean fuel mixture code which can show up as a catalytic converter issue.

Let me know.

Joe

Sep 11, 2024 at 6:46 PM
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There is no more exhaust leak.
Just confused.
Monitors go ready but CEL doesn't go off at same time....Perhaps I need to do more cycles...
I've read that CEL will go away with Drive Cycles... I've been trying..
Thanks..

Sep 11, 2024 at 7:08 PM
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I replaced the converters.
Sep 11, 2024 at 7:10 PM
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JACOBANDNICKOLAS
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Hi,

You need to clear the codes. Are you able to do that?

Joe
Sep 12, 2024 at 7:34 PM
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Yes, I cleared the codes and they return...
Have checked all O2 sensors with meter..
All working properly....
Sep 13, 2024 at 4:55 AM
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JACOBANDNICKOLAS
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Hi,

There are other things that can cause the code to set. However, it is odd that the converters are new.

I have a few questions. Has the vehicle ever been tuned up yet? Specifically, are the spark plugs original?

Also, have you checked fuel pressure to see if it is within the manufacturer's specifications?
If you haven't checked, I would. A lean or rich fuel mixture can lead to these codes. Here is a link that shows how it's done.

https://www.2carpros.com/articles/how-to-check-fuel-system-pressure-and-regulator

I attached the fuel pressure specifications below. Also, do you have a live data scan tool? If you do, we need to watch the O2 sensor voltages.

Here is a link that explains how that is done:

https://www.2carpros.com/articles/how-to-test-an-oxygen-sensor-02-sensor

I realize the sensors are new, but there could be a wiring issue causing them to not work properly.

Try these things and let me know what you find.

Take care,

Joe

See pic below.
Image (Click to enlarge)
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Sep 13, 2024 at 8:29 PM
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Hi Joe,

Voltage for sensors is correct..
I considered plugs....
Have them already and will try to change today....
Also...Will drive more today...
To add a few more Drive Cycles..
Will also check the Fuel Pressure per your advice..
Thank you
Sep 14, 2024 at 4:05 AM
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JACOBANDNICKOLAS
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Hi,

Thanks for the update. Let me know how things work out for you.

Joe
Sep 14, 2024 at 8:56 PM
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Yes Joe...Will do
I'm Moving Very slow..
Got Older...
Thanks
Sep 15, 2024 at 5:42 AM
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JACOBANDNICKOLAS
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Hi,

No problem whatsoever. I'm the same way. LOL

Take care of yourself,

Joe
Sep 15, 2024 at 6:29 PM