Will not build pressure after reduction fluid (DEF) pump replacement
I replaced the pump module because the pressure sensor was faulty; it would read high pressure, but would read 8-12 PSI without the pump running. Now, with a new OEM pump module, it will not build pressure. The pressure signal is .71 V; I briefly saw a very slight increase, then back to .71 V. I added 5 gallons of fluid upon assembly.
I am using an Apollo D8. The pump does run in both functional tests- “Reductant Pump” and "Reductant System Leak Test". The functionality of both tests is terrible (Snap-on sloppy programing), but the pump does run (confirmed audibly). I even ran it with the injector disconnected, and got no flow. No DTC is setting.
Help will be appreciated.
You need to prime it first marlin. Also make sure the little o rings are in place.could be sucking air but after replacing it I would think it's a priming issue. Hth
Prime it by what method? SI simply states to perform the system leak test, watching for the pressure to reach 78 (IIRC) psi. I don't know what o-rings you have in mind, but a new assembly should not need repairs. But maybe it does, which is what I am trying to figure out.
Marlin. If the DEF injector is disconnected from the exhaust, the gasket must be replaced, just like is required on an L5P. When you get the system up and running, I'd recommend doing the Reductant Fluid Injector Quantity Test and look for > 25ml DEF in a graduated container to ensure that sufficient volume is injected. The test usually runs for quite some time before it completes, so the…
I'm not familiar with that 2.8l setup but on the 6.6 and others the def pumps come with little plastic syringes to fill the pump before you install it. If the pump came all inclusive in a tank assembly maybe try pressurizing the tank with some air in the filler neck while running the pump to help push the fluid through…
I am not sure why you think this is the same, but maybe some years are. This unit is removed and installed through the bottom of the tank. Here is a link to a listing with photos. gmpartscenter.net/oem-parts/gm-m…
Hi Marlin. As Jonathan mentioned, if the system doesn't prime, you will need to do that, by disconnecting the supply at the injector. It appears from your account that you've already BTDT to no avail. Review Doc # 5612590 #20-NA-110: Information on Diesel Exhaust Fluid (DEF) Pump Unable to Build Pressure After Replacement - (Jan 13, 2022) For reference in GM SI. Priming begins at Step 10 of…
I will try again on Monday, hoping that a day plus of sitting will help. But what is the deal with that? It's a fresh new unit! What kind of filter dries out before contacting the fluid which it filters? I had found that TSB in an earlier search, but it only is written to apply to later model years.
Maybe it takes more time to saturate the filter media and air bubbles in the DEF can cause functional issues The bulletin clearly includes … LWN models. Maybe the version of the bulletin that you have was not updated to include 2016 LWN, but it is clearly listed in GM SI. I recalled the bulletin, since it relates to the system in the L5P and the no longer available in Canada, LH7 1.6L…
Please post the document which you are viewing, or a link to it. It is not provided for this vehicle in ProDemand or Direct-Hit. Here is the link to what I viewed. static.nhtsa.gov/odi/tsbs/2020….pdf
Marlin, the other procedures that I listed, will be associated with and/or linked from the pump replacement document 4124107 that Eric has posted with steps 10 and on. This document supports system diagnostics beyond the initial pump prime. Reductant Fuel Injector Quantity Test doc # 417804 - Ensures that the system functions properly - DEF volume and spray are verified
I don't keep a subscription to TDS. I am surprised by these issues with SI from Direct-Hit, as it has seemed to be quite reliable; I don't have much confidence in Pro-Demand, but the two match in this case. I also wonder why there is a discrepancy with the model year coverage in the TSB. Any testing was not included in this case, as the only fault was the pressure sensor. BTW, what is the…
Document 4124107 ends at step #9. What are you seeing? This is strange.
Marlin, Here is what I'm seeing for the replacement of the pump module. - NEW emission reduction fluid supply pump module seal (3) @ emission reduction fluid supply pump module (2) » Install - Emission reduction fluid supply pump module (2) @ emission reduction fluid tank (4) » Install - Bring the emission reduction fluid supply pump module in the installation position. - The locator tab…
Where did you get this? It has additional info compared to ProDemand and Direct-Hit.
AllData, under Emission Reduction Fluid Supply Pump Module Replacement. Here is the tree I followed, - Powertrain Management - Emission Control Systems - Diesel Emissions Fluid (DEF) System - Diesel Emissions Fluid Pump - Service and Repair - Removal and Replacement - Emission Reduction Fluid Supply Pump Module Replacement There are 8 steps for removal and then the 10 I listed for…
So, Direct-Hit and Pro-Demand are incomplete. Either GM updated the SI and these providers didn't update theirs, or they just left some out. In installation, they both are missing step #9 (Fill the emission reduction fluid tank.). They also do not state to drain it, which is obviously erroneous. Regardless, the complete specified procedure didn't work either. I ran the pump so long that I was…
After struggling with the missing information for newer vehicles on Direct-Hit I dropped them last year and switched to AllData. Even though Direct-Hit would provide the information when asked for it, I was unhappy with the extra time spent and work delays waiting for the information. It wouldn't have been so much of a problem if it was a rare event but there is/was a lot of missing…
When I tried it a some years ago, the Direct-Hit info that I researched match GM SI, but it wanted to know the fix, which was a PITA. I've worked off site for the past 4 plus years so can't compare, but with SI being volatile and updated regularly, I do expect that there could be some issues with external updates and missing information, as you have encountered. Agreed with the format of…
Thank you for looking this up. I have been frustrated with both Direct-Hit and Pro-Demand being slow to upload info for model years, but the first has gotten worse and the latter has gotten better. I find it odd that in this case they have matching incomplete procedure steps. That is not something that I associated with Direct-Hit, but now I wonder how much we are missing. It is reminiscent of…
I've had AllData in the past and been happy with them. The one thing that bothered me about AllData was their subscription requirement. I just don't like being required to buy a one year subscription with no easy way out. When I was using Identifix I would need to request info 2 to 4 times a week. That doesn't seem like much since I use my SI constantly during the day but it slowed down my…
I finally disconnected the line from the pump, then let it sit for a while until fluid began to seep from the nipple. After reconnecting the line, the pump built pressure very quickly, Another note. Be very careful with the retainer clip. It is a very lousy design, seemingly intended the spread the fingers when the center of the exposed tab is pressed. This one did not release, so I carefully…
Hi Marlin. Glad you got it sorted. I assume that you mean this clip? I agree, it is a poor design and the links that identify various types of line coupler removal in SI, do not provide a clear image for removal from the pump module. The inner ring does not deform enough to expand it far enough to be moved over the shoulder on the plastic injector supply line pipe to release the coupling from…
No, it's this one (broken, but set together for the photo). I wonder if the line, which is the superceded replacement, has that retainer type.
I went through this on a 6.6 duramax a while back. It would show pressure on the scan tool fail all tests. Pulling the line off the pump and only a dribble would come out. I replaced it three times with a factory gm part. The 3rd pump built pressure instantly and gave full flow.
This never showed more than negligible pressure until it worked normally. It is really frustrating.
Thank you for the information about that clip design. The service information about the various clip designs does not include the one that I had. What application is the style that you showed used for?
Hi Marlin. It is always useful to share, particularly when clips like those can be a struggle! I couldn't pull the line off, even though I'd squeezed the clamp ears to the stops. A large flat blade screwdriver easily pushed the coupler off. I encountered something similar while working at the dealership when Chevy Sprints were a current model. You could expand the external fuel filter spring…
I am really baffled by their variety and over-complexity of retainer designs. It really should not be any big deal, and isn't a matter of correcting a problematic design.
Agreed, but that's not GM, its the component supplier companies that design and engineer the systems that make a “better widget”. I guess that engineers need something to justify their existence! FWIW, the diagrams in SI show retainer designs spanning about 30 years. It's the same with terminals and connectors being determined by the supplier. With large companies and the necessity of having…