# Cel p21dd



## 567Chief (Feb 25, 2013)

So I finally found a setup that would read my CEL. Turns out is's a P21DD. This code is a DEF tank heater open circuit that's detected by low conductance in the heater. Has anyone else experienced this? Is this covered under warranty considering I just turned 37K miles? I'm thinking it's a loose or bad plug because it's been way above 12 degrees around here for a while and the CEL light has only been on for a couple of weeks. Suggestions?


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## diesel (Jun 8, 2013)

I think someone else had that one a while back and posted about it.


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## obermd (Mar 3, 2012)

Depending on the actual problem it may be covered under the emissions warranty.


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## plasticplant (Mar 26, 2013)

There have been a few of us with this issue (including myself) and there are a few threads about it; but really they are not of much help. This has been my experience so far. I got a CEL at 48K (4th of July weekend) and took it to the dealer to have them check it out. The CEL was from the P21DD code. They cleared it and told me to come back if it came back on. The next day it was back. I cleared it with my Ultragauge and it came back the same day. I called the dealership back and they told me to bring it in. I made an appointment for that Saturday and drove with the CEL for about 5 days (does not hurt drivability of the car). Saturday came and I fired up the car to head to the dealership; and guess what? The CEL goes off. I get to the dealership and explain what happened and they check the car out. The code was still stored, so they ordered the part and said they had to do some investigation as to if it will be covered under the emissions warranty. The service guy sounded confidant from the information he found that it would be. He told me he would call me when he found out for sure. I still haven't heard back from them yet, but I plan on calling today. I' am however still CEL free. I'll update when I get more info on the fix and if it was covered by warranty or not. FYI, one other member stated that he had to pay for the repair, but it did not fix his problem (if I remember correctly).


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## 567Chief (Feb 25, 2013)

plasticplant said:


> There have been a few of us with this issue (including myself) and there are a few threads about it; but really they are not of much help. This has been my experience so far. I got a CEL at 48K (4th of July weekend) and took it to the dealer to have them check it out. The CEL was from the P21DD code. They cleared it and told me to come back if it came back on. The next day it was back. I cleared it with my Ultragauge and it came back the same day. I called the dealership back and they told me to bring it in. I made an appointment for that Saturday and drove with the CEL for about 5 days (does not hurt drivability of the car). Saturday came and I fired up the car to head to the dealership; and guess what? The CEL goes off. I get to the dealership and explain what happened and they check the car out. The code was still stored, so they ordered the part and said they had to do some investigation as to if it will be covered under the emissions warranty. The service guy sounded confidant from the information he found that it would be. He told me he would call me when he found out for sure. I still haven't heard back from them yet, but I plan on calling today. I' am however still CEL free. I'll update when I get more info on the fix and if it was covered by warranty or not. FYI, one other member stated that he had to pay for the repair, but it did not fix his problem (if I remember correctly).


That is just the feedback I was looking for. I have jiggled every plug in the vicinity of the DEF tank hoping it's nothing more than a bad connection. I'm going to clear out my CEL in the morning and see if it stays off. Thanks for taking the time to compose your response!


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## cmsdock (Feb 16, 2014)

I had mine replaced at 85k in miles. You can find the part online for around $160. Your dealership will charge for an hour and a half for labor.


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## plasticplant (Mar 26, 2013)

567Chief said:


> That is just the feedback I was looking for. I have jiggled every plug in the vicinity of the DEF tank hoping it's nothing more than a bad connection. I'm going to clear out my CEL in the morning and see if it stays off. Thanks for taking the time to compose your response!


Just to update (as promised). I called the dealership and they told me that the part(s) would be covered under the emissions warranty. Hopefully they won't change their tune once the work is completed. I'm still unsure what exactly they will be replacing, but when I get the part number(s) from them, I'll be sure to share. I go in on Monday (the 20th) to have the car serviced.


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## 567Chief (Feb 25, 2013)

plasticplant said:


> Just to update (as promised). I called the dealership and they told me that the part(s) would be covered under the emissions warranty. Hopefully they won't change their tune once the work is completed. I'm still unsure what exactly they will be replacing, but when I get the part number(s) from them, I'll be sure to share. I go in on Monday (the 20th) to have the car serviced.


Thanks again plasticplant- I hope all goes well for you!

After jiggling all of the plugs in the vicinity of the DEF tank and clearing the code, it reappeared today. I sure wish someone could definitively say that this is covered, preferably a GM customer service rep. I cannot see why this would not fall under the emissions 80K coverage. No doubt it is part of the emissions system. Not standing behind these components will not help GM get gassers to make the switch to diesel. Considering the number of people getting this code, I believe the part or plug must be defective. How does a DEF heater fail in the summer?


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## plasticplant (Mar 26, 2013)

No problem at all! Always happy to help. CELs can be a huge PITA. I had the repair done today and it was in fact covered under warranty; they didn't specify which one though (drivetrain or emissions). The part number they replaced was 22978800 and it was for the reservoir assembly. It looks like you can't just replace a sensor, but the whole assembly is pulled out and replaced. I've got about 100 miles on it since the repair and no CEL has appeared. Hopefully this starts another 50k+ trouble free miles.


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## e-iowa-o (Sep 2, 2015)

I have the same code. CEL has been on a couple of months. Winter is coming. I guess it will be a good time to take it in if t might be covered. Emissions had 80k warranty?

I notice when the CEL is on the remote start won't work.


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## e-iowa-o (Sep 2, 2015)

dealer said it would be covered under emissions but when I took for them to check it out they said only covered on California emissions?? said they could cover part of it. Asked me to pay $281 as the part was $580 from Chevy. 

I'm just going to get it back and buy the part online


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## diesel (Jun 8, 2013)

e-iowa-o said:


> dealer said it would be covered under emissions but when I took for them to check it out they said only covered on California emissions?? said they could cover part of it. Asked me to pay $281 as the part was $580 from Chevy.
> 
> I'm just going to get it back and buy the part online


If I were you, I would send a PM to GM Customer care on here and get their help.


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## KpaxFAQ (Sep 1, 2013)

e-iowa-o said:


> I have the same code. CEL has been on a couple of months. Winter is coming. I guess it will be a good time to take it in if t might be covered. Emissions had 80k warranty?
> 
> I notice when the CEL is on the remote start won't work.


Only certain codes cause that. I had an active shutter related CEL for months that didn't hinder remote start. The minute I had a glowplug go bad it wouldn't remote start for that code though.


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## diesel (Jun 8, 2013)

KpaxFAQ said:


> Only certain codes cause that. I had an active shutter related CEL for months that didn't hinder remote start. The minute I had a glowplug go bad it wouldn't remote start for that code though.


Interesting! I thought every CEL did that. Still plenty to learn about this car!


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## e-iowa-o (Sep 2, 2015)

diesel said:


> If I were you, I would send a PM to GM Customer care on here and get their help.


I did that last Friday. haven't heard anything back. probably give it another day or two then just find th part online and get one ordered. I understand there is a back order problem. got down to 5 degrees here a cpl nights ago. can't afford to fart around too much longer..


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## diesel (Jun 8, 2013)

e-iowa-o said:


> I did that last Friday. haven't heard anything back. probably give it another day or two then just find th part online and get one ordered. I understand there is a back order problem. got down to 5 degrees here a cpl nights ago. can't afford to fart around too much longer..


Usually they are pretty good about that sort of thing. I wonder if they are off for the holidays.


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## e-iowa-o (Sep 2, 2015)

diesel said:


> Usually they are pretty good about that sort of thing. I wonder if they are off for the holidays.


They got back to me today. 8yr/80k emissions warranty doesn't include this part. only major items like Cat and programming issues. So, off I go to order one. thanks for your input.


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