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Discussion Starter · #1 ·
Hello. I have a 2020 Silverado 2500 LTZ Duramax with approximately 15000 miles on it. 90% of the miles are highway miles while pulling a 5th wheel trailer. This is also my first diesel truck. This past weekend we were on a trip about 300 miles from home when the Engine Malfunction Light came on. I went to the nearest Chevy dealer, and they pulled codes P0421 - Catalyst 1 Low Efficiency (Test failed since code cleared), P0422 - Catalyst 2 Low Efficiency (Current), and P24A0 - Closed loop Diesel Particulate Filter (DPF) Regeneration control at limit - Low Temperature (Test failed since code cleared). The dealer said they couldn't fit me in to look at the issue, but the truck should be fine to get me back home.

On my way home, the display suddenly read the engine was in reduced power mode, and the truck certainly felt like it didn't have much power. I made it home and took it to my local dealer who also pulled codes P0422 and P2463. The service ticket also read "Freeze frame data showed 96% soot mass accumulation. Quantity tested the indirect injector was supplying proper amount of fluid. Performed service regeneration to clean the system. No further issue. Cleared code and test drove."

My questions are 1) what are possible causes for this issue and 2) what can I do to help prevent it from happening again?

Thanks in advance for any help!
 

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2015 High Country Duramax
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Something could have potentially either interrupted a regen, or for whatever reason it just never was able to complete a regen.

Short of getting rid of the offending parts, there really isn't anything you can do to prevent it. You could use either a scan tool or some of the monitors will allow you to run a parked regen. But I will warn you, if you do a parked regen, you absolutely need to be very mindful of where you park.

You need to have the truck, mainly the under side and exhaust exit, well clear of anything flammable or subject to high heat. During the regen the exhaust gas temp can reach to around 1200-1400 degrees. So anything around that can catch fire is a no go.

It's also not super ideal for the truck either. Without the air flow of driving, it will get really hot underneath and under the hood. I've had trucks melt the plastic and burn the paint before. I put a large fan facing under the truck when I do parked regens on pickups at work. They just don't handle the heat nearly as well as the heavy trucks can.
 

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Discussion Starter · #3 ·
Hey Trax...I appreciate the quick reply! I'll keep monitoring when the truck is in regen mode and I may pull the trigger on a scan tool. I was actually looking online for something similar, so it may be a future purchase. Thanks again!
 
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