2012 Duramax 6.6L LML — P20B9

Andrew Technician De Motte, Indiana Posted   Latest   Edited  
Case Study
Driveability
2012 Chevrolet Silverado 2500 HD LT 6.6L (8 LML) 6-spd (1000)
P20B9 - Reductant Heater "A" Control Circuit/Open

Here is another Duramax case study. More than anything I want to share with you all on how to reset the warning message once the repair is completed. I will be adding to this one later on a 2015 with the same issue. I want to walk you all through it with GDS2 as well. 

docs​.​google​.​com/presentation/d…

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Bill Technician
Rosetown, Saskatchewan
Bill
 

Nice Andrew! Does the DEF tank need to be completely filled before running the resets and testing the heaters? Is there a reductant data reset that should be performed after the level reset? I seem to remember after the all 3 sensors read active and the level reset is performed to bring PID to 100% that the reductant data reset should be performed afterwards. I think there are differences from

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Andrew Technician
De Motte, Indiana
Andrew
 

I always re-fill the tank. You do not have to do it but for me these trucks have a special policy until 120k for the heater. So I refill every one of them. You are correct year to year is different. I got to be honest I see these a ton, and I still have to look it up all the time. I'll never forget the first one I did and could not get the message to reset. I will also confirm a Snap-On scanner

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Mario Diagnostician
Weston, Florida
Mario
 

Loving the slide format, great post Andrew 👍

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Andrew Technician
De Motte, Indiana
Andrew
 

Thanks Mario... for me I find it the best way to let people follow my diagnostic flow, and reasoning.

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Michael Owner/Technician
Jurupa Valley, California
Michael
 

Nicely put together slides of repairs (visuals are awesome); you used the Tech2 for the repair I see - did you purchase the tech2 aftermarket or off the truck?

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Andrew Technician
De Motte, Indiana
Andrew
 

I used Tech2Win for this one (PC based) I am a GM dealer tech so we have Tech2's but I use Tech2 Win most of the time through my MDI2.

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Glen Owner/Technician
Arthur, Illinois
Glen
   

I use these for those type of DEF fittings & lots of other fuel line connectors

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