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Code p20b9 and code p21dd. Reductant heater and codes P20B(

Customer Question
Code p20b9...

Code p20b9 and code p21dd

Mechanic's Assistant: Just to clarify, what's the exact code? And have you tried to reset it?

Reductant heater and codes P20B( P21DD

Mechanic's Assistant: What is the model/year of your GMC?

P20b9 P21DD 2013 gmc 6.6 diesel 6.6 liter

Mechanic's Assistant: Are you fixing your vehicle yourself? What have you tried so far?

Yes replaced heater kit GM part # 23379348

Submitted: 6 months ago.Category: GMC
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Answered in 1 day by:
1/5/2018
GMC Mechanic: Chris (aka-Moose), GMC Technician replied 6 months ago
Chris (aka-Moose)
Chris (aka-Moose), GMC Technician
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Are you asking for the diagnostic steps for the codes you have?

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GMC Mechanic: Chris (aka-Moose), GMC Technician replied 6 months ago

Hello, Chris here again,

I am checking in to make sure you got everything you expected from my answer. The option to rate my response or reply is still available. I want to make sure you were pleased with what you paid for.

Thanks Chris

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