Replacing DEF Pump

3311 Views 19 Replies 6 Participants Last post by mjs, 18 d ago

Ohio Boss

Discussion Starter · 8 mo ago

Got the Poor Exhaust Fluid message and limp mode warning.
DTC code was for Low Reductant Pressure.
Did some checking and found a TSB indicating my 2016 may have a bad pump and should be replaced.
Pump cost from Rock Auto was $522.59 and 5 days shipping.
Dealer estimate to replace is $2500 - $3500.
Yeah, Right!
Drop the spare.
Remove heat shield - 3 plastic push fasteners.
Remove filler tube at tank and snake a drain line in and drain the DEFF. 5 gallon bucket if tank is full.
Remove 4 nuts to remove 2 support/protection bars.
Remove 5 push fasteners to remove outer cover of tank.
Disconnect injector line at pump and disconnect electrical connectors.
Remove 5 bolts and carefully drop tank down and remove line on top of tank
First time it goes slow.
Goes back together much faster.
Save your cash.
You can do this without even jacking the truck up.

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6speedTi

· #2 · 8 mo ago

Good write up. One more thing to add. When you install a new pump GM says to let the DEF soak into the pump because there is a filter that needs to be saturated so you won't get a cavitation issue similar to a pump that needs a prime. GM has TSB covering this. They recommend a 24 hour soak period but I'm sure it doesn't take that long.

Legends117

· #3 · 4 mo ago

Hi - noob here. 2 questions, can you point me to a diagram that shows the where? And second, did you have to do a regen or anything? I watchee a video that showed the Mechanic doing a regen and level calibration...so just wondering. Thanks

otoole

· #4 · 4 mo ago

"Remove 5 bolts and carefully drop tank down and remove line on top of tank"
What is this step for? Doesn't the pump/heater assembly come out the bottom of the DEF tank?

Scruvs

· #5 · 4 mo ago

Thanks Ohio Boss for the write up. I think I'm going to try this on my own to save the money.

How is the pump disconnected from the tank? Does it turn to unlock or is it clipped in somehow?
Otoole, I'm wondering if the tank has to be dropped to disconnect a line on the top of the tank that is connected to the pump? maybe?

And, thanks 6speedTi for mentioning the TSB. I looked it up and found it here.

Legends117, does this diagram help?

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otoole

· #6 · 4 mo ago

Scruvs

I don't know about the line on top of the tank. I am wondering if I missed that. When I replaced the DEF pump/heater in my 2016 Colorado 2.8l I only saw connections to the pump on the bottom.

I did not drain the DEF out in advance. I got a 10gal plastic tote bin and let the DEF out slowly when I pulled the pump.

The pump is held in with a large silver locking ring. I pounded the ring with a large screwdriver and a hammer to get it to unthread. Be careful not to hit it too hard as the tank is plastic.

Scruvs, let me know what you find out about the line on top.

Scruvs

· #7 · 3 mo ago

My pump arrived today from Rock Auto $500 all-in. I started this today, but won't finish until tomorrow or the next day. I can't get my lock ring off, so I ordered a lock ring removal tool from Amazon that will be here tomorrow.

Otoole: I am unable to drop the tank. I am unable to remove two of the five bolts that hold the tank (the two facing the front of the truck, they are actually nuts, and the other three are bolts). These two nuts are stripped or something, and I can't see what's happening on the bolt side on the top of the tank. I replaced the three bolts and the tank seems secure.

My tank is drained using the Harbor Freight drill pump method with 5/8" garden hose and a 5 gal bucket. I cannot see any reason to drop the tank other than some spillage from remaining def in the tank. This video below is for a 6.6L, but it shows that there are no connections on the top side of the tank or topside of the pump.

I think when Ohio Boss says "remove line on top of tank" he's might be talking about the injector line near the pump that is clipped into the tank shield. Unclipping this is necessary to drop the shield to access the lock ring. From underneath, I can't see any lines running to the topside of the tank. I'll know more when I unlock the pump.

-Scruvs

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Scruvs

· #8 · 3 mo ago (Edited)

Thanks to you folks on this board I was able to get this fixed. I'll add photos to the steps Ohio Boss posted.

Note that I ended up here because of code P1050. First, I conducted the resistance test to diagnose whether it was (1) the sensor in the pump; or (2) the control module. For me, it was the pump.

Drop the spare.
Remove heat shield - 3 plastic push fasteners. For these, you pull the the center push pin down with a trim removal tool. I then had to reach above and pinch the fastner and pull down from the bottom.

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Remove filler tube at tank and snake a drain line in and drain the DEF. 5 gallon bucket if tank is full.
I followed the tutorial on draining the Def tank. I bought a 15ft. 5/8" garden hose and a female to female connector along with the drill pump and an old 5 gallon bucket.

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Remove 4 nuts to remove 2 support/protection bars.

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Remove 4 push fasteners to remove outer cover of tank. (I edited this to say "4" fastners). I only had 4. Pop the center out and pull down.

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Disconnect injector line at pump and disconnect electrical connectors.
Unclip wire from tank shield and disconnect the two wire harness plugs that are connected to the control module.

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Unclip the DEF injector line.

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Disconnect the electrical connector to the injector.

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Push up on the white clip with a big flathead screwdriver while sliding the injector off.

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At this point, the tank cover and shield can be dropped. I'll show more connections in the next post.

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10

Scruvs

· #9 · 3 mo ago

Photos continued...
After the tank cover and shield are dropped, disconnect the harness from the pump.
Unlike Ohio Boss, I did not drop the tank.
I did not Remove 5 bolts and carefully drop tank down and remove line on top of tank.
I replaced the pump with the tank still installed.

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Note, the location of the tab on the pump. The tank under this tab is engraved "Locator" to show the location of this tab. The tab points to the corner of the control module.

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I needed a lock ring removal tool like this and 2ft. 1/2" breaker bar to release my lock ring.

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Arrows showing all electrical/injector connections. Circles showing clips for the lines in the tank cover.

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Last thing to do is install the access cover with the two plastic tabs and the single push fastener, and replace the spare tire heat shield with its three plastic fasteners.

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Don't forget to reconnect your DEF fill line to the tank if you didn't immediately replace it after draining the tank.

I added one gallon of DEF, reconnected the negative battery cable. My CEL for P1050 was gone. I did not have to run any scan tool tests to reset or delete the CEL.
DEF Fluid level read "OK."
Because I disconnected the battery, I had to drive the truck for a couple minutes to relearn Tire Pressure.
Also, the display showed outside temperature of 32 degrees F in Florida, which was wrong. I learned that the truck has to be driven at least 20mph for five minutes without dropping below 20mph.
I drove the truck to pick up another 2.5 Gal DEF and added it to the tank. I will not top off the tank, if I don't have to.
I let the DEF sit overnight to soak the pump. The outside temperature was correct in the morning and "Possible Ice warning" was gone despite me not driving 20 mph for five minutes.

-Scruvs.

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6

Scruvs

· #10 · 3 mo ago

Otoole:

Here is an image of the top of the inside of the tank looking up from the bottom where the DEF pump sits. I don't know if that is some sort of vent that would have to be disconnected to drop the tank, but it was not connected to the pump. So, I don't think you missed anything by not dropping the tank.

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otoole said:
Scruvs

I don't know about the line on top of the tank. I am wondering if I missed that. When I replaced the DEF pump/heater in my 2016 Colorado 2.8l I only saw connections to the pump on the bottom.

I did not drain the DEF out in advance. I got a 10gal plastic tote bin and let the DEF out slowly when I pulled the pump.

The pump is held in with a large silver locking ring. I pounded the ring with a large screwdriver and a hammer to get it to unthread. Be careful not to hit it too hard as the tank is plastic.

Scruvs, let me know what you find out about the line on top.

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6speedTi

· #11 · 3 mo ago

You mentioned level read OK after new pump installed. Did you or were you able to get the actual percentage amount in the tank? I ask this because I recently replaced my DEF pump on my 2018 Chevy Cruze. It read OK after I filled it up to full but using my phone app Gretio and Blue Driver the percentages did not match actual level. With the Gretio app you can do a DEF level calibration. Unfortunately I haven't figured out at what level to do this since my percentages are off even after the calibration but I still have the OK. My percentages are hanging around the 60's percentage level.

Scruvs

· #12 · 3 mo ago

I will try this today with my Gretio app. I know that before I replaced my pump, the Reductant Level read 45% despite being full. But, the sensor was bad on the pump, so it may not have been accurate. I will check today. I filled with approximately 3.5 gal, so I expect the Reductant Level to read approximately 67% (3.5/5.2), but we'll see today after work, and I will let you know.

6speedTi said:
You mentioned level read OK after new pump installed. Did you or were you able to get the actual percentage amount in the tank? I ask this because I recently replaced my DEF pump on my 2018 Chevy Cruze. It read OK after I filled it up to full but using my phone app Gretio and Blue Driver the percentages did not match actual level. With the Gretio app you can do a DEF level calibration. Unfortunately I haven't figured out at what level to do this since my percentages are off even after the calibration but I still have the OK. My percentages are hanging around the 60's percentage level.

6speedTi

· #13 · 3 mo ago

Scruvs said:
I will try this today with my Gretio app. I know that before I replaced my pump, the Reductant Level read 45% despite being full. But, the sensor was bad on the pump, so it may not have been accurate. I will check today. I filled with approximately 3.5 gal, so I expect the Reductant Level to read approximately 67% (3.5/5.2), but we'll see today after work, and I will let you know.

My sensor was bad so I thought. After getting the Gretio app and realized it had a calibration feature I saved my old pump and will try calibrating it someday to see if that was the original cause of my failure. If so then I probably spent $500 on a new pump for nothing. I am starting to believe that if a quantity level issue occurs on the pump assembly a calibration might correct the problem. Unfortunately many owners don't have the capability to do a reset or a recalibration if that is the only issue with the pump. Keep your old pump if you still have it. It might be a simple fix to a very expensive part.

Scruvs

· #14 · 3 mo ago

Thanks. Trash goes out tomorrow, so I'll pull my pump from the bin and save it, just in case. I thought about saving it anyway in a pinch because the pump works, its just the "sensor" that sets off the CEL. This way, if I'm ever in limp mode and can't get a part right away, I'll have a backup.

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Scruvs

· #15 · 3 mo ago

The Reductant Level in the Gretio app read 47.4%. That's a bit lower than I would expect. I didn't see a calibration command, but I saw a Reductant Level Reset command. I was scared to run it because I don't know if it's supposed to be reset when it's full, and I think I am at about 65%. I will keep an eye on this and see what the level reads when I get my 30% warning, but that might be months.

6speedTi said:
You mentioned level read OK after new pump installed. Did you or were you able to get the actual percentage amount in the tank? I ask this because I recently replaced my DEF pump on my 2018 Chevy Cruze. It read OK after I filled it up to full but using my phone app Gretio and Blue Driver the percentages did not match actual level. With the Gretio app you can do a DEF level calibration. Unfortunately I haven't figured out at what level to do this since my percentages are off even after the calibration but I still have the OK. My percentages are hanging around the 60's percentage level.

6speedTi

· #16 · 3 mo ago

Scruvs said:
The Reductant Level in the Gretio app read 47.4%. That's a bit lower than I would expect. I didn't see a calibration command, but I saw a Reductant Level Reset command. I was scared to run it because I don't know if it's supposed to be reset when it's full, and I think I am at about 65%. I will keep an eye on this and see what the level reads when I get my 30% warning, but that might be months.

Yes the level reset function was what I meant. You are correct about resetting it. I don't know if it has to be reset at empty (0%) or full or some other procedure like adding a specific amount depending on vehicle make and model. My cruze was full. It showed 89% at first. I did the level reset. Went to 67%. Started countdown over time and then around 62% it would jump back up to 67%. It did the same thing repeatedly. This leads me to believe the level reset needs to be done at a specific level to read correctly. I'm sure the dealership technicians must know.

Ohio Boss

Discussion Starter · #17 · 1 mo ago

Scruvs said:
My pump arrived today from Rock Auto $500 all-in. I started this today, but won't finish until tomorrow or the next day. I can't get my lock ring off, so I ordered a lock ring removal tool from Amazon that will be here tomorrow.

Otoole: I am unable to drop the tank. I am unable to remove two of the five bolts that hold the tank (the two facing the front of the truck, they are actually nuts, and the other three are bolts). These two nuts are stripped or something, and I can't see what's happening on the bolt side on the top of the tank. I replaced the three bolts and the tank seems secure.

My tank is drained using the Harbor Freight drill pump method with 5/8" garden hose and a 5 gal bucket. I cannot see any reason to drop the tank other than some spillage from remaining def in the tank. This video below is for a 6.6L, but it shows that there are no connections on the top side of the tank or topside of the pump.

I think when Ohio Boss says "remove line on top of tank" he's might be talking about the injector line near the pump that is clipped into the tank shield. Unclipping this is necessary to drop the shield to access the lock ring. From underneath, I can't see any lines running to the topside of the tank. I'll know more when I unlock the pump.

-Scruvs

The pump unit on mine drops in from the top. No opening on the bottom. That’s why the tank needs to be emptied. Or use a floor jack to handle the weight.

6speedTi

· #18 · 1 mo ago

Ohio Boss said:
The pump unit on mine drops in from the top. No opening on the bottom. That’s why the tank needs to be emptied. Or use a floor jack to handle the weight.

Is it possible you have an early 2016 with a production build date in 2015?

Ohio Boss

Discussion Starter · #19 · 1 mo ago

otoole said:
Scruvs

I don't know about the line on top of the tank. I am wondering if I missed that. When I replaced the DEF pump/heater in my 2016 Colorado 2.8l I only saw connections to the pump on the bottom.

I did not drain the DEF out in advance. I got a 10gal plastic tote bin and let the DEF out slowly when I pulled the pump.

The pump is held in with a large silver locking ring. I pounded the ring with a large screwdriver and a hammer to get it to unthread. Be careful not to hit it too hard as the tank is plastic.

Scruvs, let me know what you find out about the line on top.

Okay, crawled under to check mine again and you and others are correct. The access IS from the bottom. I dropped it because I did not want a Urea shower on my face. It was real easy to work on it once the tank was pulled

Reactions: 1

mjs

· #20 · 18 d ago

Replaced mine today with the GM part from Rock Auto. Dealer quote was $2000.

2107 ZR2 Diesel with 52,000 mi. You can see that there was DEF ingress into the level sensor on the old one. Seems to be a somewhat common issue? Just out of warranty though...

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