# DEF Reservoir: Definitive Explanation and Part Numbers



## pacolino (Aug 1, 2015)

Thank you, that's great info bro.

Sent from my LGMS631 using Tapatalk


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## BlueTopaz (Aug 25, 2012)

I spoke to a friend of mine that works the parts department at a Chevy dealership and he did a search for both part numbers. Seems there isn't any in the supply system and just a hand full at some dealerships. Since my Cruze is at a dealership waiting on this part, it might be a while. What he is telling me is that most dealerships will not release what they have in stock, they are keeping it for their customers. So unless my dealership gets lucky and is able to have one of the few dealerships in the country release one. I might be in my rental car for a while. This is an issue with all the trucks as well. Seems to me GM needs to step up and get some production ramped up on this part. Hopefully the new part number is also an indication that the part has been improved.


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## diesel (Jun 8, 2013)

great information! Thanks for posting!


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## BlueTopaz (Aug 25, 2012)

The dealer called. They have the part coming from Chicago. Turns out just like I said, dealerships all around us have one or two in stock but they will not let them go. Turns out she said that Hendrick had two but they wouldn't give them up. I should have went there to get it fixed since that is where I purchased the Cruze from. Only thing is that dealership is 80 miles away and the one I'm at now is only 25 miles away.


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## MP81 (Jul 20, 2015)

Couple months old, I know - but this is the part being replaced when the heater is throwing the code, yes? Do not have to replace the entire tank?


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## DslGate (Jun 29, 2016)

Sounds to me like the heater and level sensor are one piece or can not be ordered separately and that the DEF canister is separate . Apparently, the canister is NOT what is going bad in these, but just the heater ( which can not be replaced separately from the level sensor. ) @*MP81

does Anyone have a diagram of assembly??? *


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## diesel (Jun 8, 2013)

DslGate said:


> *
> does Anyone have a diagram of assembly??? *


Source: 22978800 RESERVOIR-SEE NEW PART NUMBER 23377881 for 2014 Chevrolet Cruze - It's #15 in the numbered illustration


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## revjpeterson (Oct 2, 2013)

MP81 said:


> Couple months old, I know - but this is the part being replaced when the heater is throwing the code, yes? Do not have to replace the entire tank?





DslGate said:


> Sounds to me like the heater and level sensor are one piece or can not be ordered separately and that the DEF canister is separate . Apparently, the canister is NOT what is going bad in these, but just the heater ( which can not be replaced separately from the level sensor. ) @*MP81*


Yes, this is the part to replace with the P11D7 and/or P20B9 code. As I stated in the OP, this is a single canister-shaped assembly, containing the level sensor, heater, and some other components. The deceptive name "reservoir" has given many people the impression it is the tank; it is not. It basically contains everything except the tank and pump. The reservoir drops into the top of the tank, and the pump mounts to the top of the reservoir after it is installed.


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## vwgtiglx (Jun 13, 2013)

revjpeterson said:


> Yes, this is the part to replace with the P11D7 and/or P20B9 code. As I stated in the OP, this is a single canister-shaped assembly, containing the level sensor, heater, and some other components. The deceptive name "reservoir" has given many people the impression it is the tank; it is not. It basically contains everything except the tank and pump. The reservoir drops into the top of the tank, and the pump mounts to the top of the reservoir after it is installed.


I just had this part replaced this past week at my dealer @ 29,000 miles, at NC, under B2B warranty. It took 2 days to get the part. My CEL code was P205B - Reductant Temp. Sensor Out of Range. Work order said; Level & Temp. Emission Reduction Fluid Control Module (incl. filter) part #23377881 replaced. The car did not show any symptoms other than frequent Regen's, which it still does and has been doing for the past 6 months. The Service Rep. thinks this may have something to do with it but I seriously doubt it. We shall see what we shall see. He said the NOx sensor recall is still pending and we will all be notified when the parts are available.


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## MP81 (Jul 20, 2015)

revjpeterson said:


> Yes, this is the part to replace with the P11D7 and/or P20B9 code. As I stated in the OP, this is a single canister-shaped assembly, containing the level sensor, heater, and some other components. The deceptive name "reservoir" has given many people the impression it is the tank; it is not. It basically contains everything except the tank and pump. The reservoir drops into the top of the tank, and the pump mounts to the top of the reservoir after it is installed.


I think the reservoir is referring to the small sump it comes with - essentially a reservoir for the heater. Sometimes (at least here, don't know for sure about GM) you are limited on what you can call a part, so you go with what fits the best, even if it doesn't at all.



vwgtiglx said:


> He said the NOx sensor recall is still pending and we will all be notified when the parts are available.


My guess is that "parts" relate to the ECM tune.


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## diesel (Jun 8, 2013)

vwgtiglx said:


> I just had this part replaced this past week at my dealer @ 29,000 miles, at NC, under B2B warranty. It took 2 days to get the part. My CEL code was P205B - Reductant Temp. Sensor Out of Range. Work order said; Level & Temp. Emission Reduction Fluid Control Module (incl. filter) part #23377881 replaced. The car did not show any symptoms other than frequent Regen's, which it still does and has been doing for the past 6 months. The Service Rep. thinks this may have something to do with it but I seriously doubt it. We shall see what we shall see. He said the NOx sensor recall is still pending and we will all be notified when the parts are available.


I don't see how the SCR could possibly have anything to do with regens, since the SCR is completely downstream of the DPF in the exhaust system.


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## Lugnut (May 4, 2017)

This issue is now covered by GM Special Policy #29400. 10 year, 120000 miles. If you have this issue, take it to a Chevrolet dealer. 

29400: Special Coverage Adjustment – Diesel Emission Fluid Tank Reservoir – 2013-2015 Chevrolet & GMC | gm.oemdtc.com


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## Badbird (May 13, 2017)

I replaced mine last year while on vacation. It was very easy, took about 25 min...When I got home, I sent my invoice to GM using their reimbursement form that was included in the O2 sensor issue/recall (I think) they mailed me a while back. Had a check for the full amount in less than 2 weeks.


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## oilburner (Jun 13, 2013)

had mine replaced 3 days ago under extended warranty.


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## thebac (Jul 29, 2017)

Been getting the P21DD code the past three days on initial startup. I just use the code reader to erase it, but I got to wondering.....would a low DEF condition, but not quite to where the "refill DEF" alert comes up, cause this code? 
Maybe the reservoir has become low enough on DEF that the heater has become uncovered so it now reads hotter and trips the code?
I've gotten almost 10,000 miles out of my tank of DEF so far, which seems high to me, it still shows "OK" but it makes me wonder.

In the end, I'll either refill the DEF tank (yeah I know....I should do that first), or take it in and get it repaired. At least it's covered.


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## BDCCruze (Jul 12, 2017)

Just bumping this as well. I'm getting the P21DD now on my CTD. I've already had the tank replaced under warranty a couple years ago. I also recently got the p24AE for the particulate matter sensor but that keeps showing as passed now. Are they related? Is it possible the back tank is causing the sensor to show bad?

If I have to replace the def tank heater again can these be done at home? Looks like 84412930 is the most updated part#


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## BDCCruze (Jul 12, 2017)

Quick update. Replaced the reservoir today. CEL is still on after around 30-40 miles but it is showing last test passed in the scan tool. I thought I read it can take like 50 miles or more to clear. Any ideas?


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## revjpeterson (Oct 2, 2013)

BDCCruze said:


> Quick update. Replaced the reservoir today. CEL is still on after around 30-40 miles but it is showing last test passed in the scan tool. I thought I read it can take like 50 miles or more to clear. Any ideas?


Do you know which code is turning the CEL on? If you replaced the DEF reservoir, you will clear the P21DD sooner or later, but the P24AE you mentioned will still be there, since it's unrelated. When I replaced my DEF heater, I had P21DD/P20B9 together (both DEF reservoir related), and they cleared on the first engine start after replacement. I have heard of P21DD taking a some miles or a few engine cycles to clear, though.


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## BDCCruze (Jul 12, 2017)

revjpeterson said:


> Do you know which code is turning the CEL on? If you replaced the DEF reservoir, you will clear the P21DD sooner or later, but the P24AE you mentioned will still be there, since it's unrelated. When I replaced my DEF heater, I had P21DD/P20B9 together (both DEF reservoir related), and they cleared on the first engine start after replacement. I have heard of P21DD taking a some miles or a few engine cycles to clear, though.


The P24AE has not came back on since the original time a couple weeks ago. I cleared codes right after getting the P21DD so I could confirm whether or not I am only dealing with 1 or 2 active codes and the P21DD is the only one that has came back on so far.

I plan on doing a 50 mile or so drive this afternoon and will report back if the light is still on.

_Edit_

Drove about 15 minutes down the road, shut off the car and turned it back on. The light went out. Drove another 100 miles or so and it stayed out. Probably just needed a second drive cycle.


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