# Differential Pressure Sensor Tubes?



## TyGeR (Oct 24, 2016)

Ok, so swapping parts trying to get rid of some codes and today I am swapping the Differential Pressure Sensor. So I find a chart on here that helps me locate the part. Proceed to change it for a new one and as I am taking off the large hose going to this part the pipe/tube feels very loose. The sensor and a broken part of tube/pipe comes out. (PIC 1). I look around on the rear of the engine and I find the other end of the tube/pipe thats connected to a bracket. (PIC 2). I trace the pipe/tube the best I can and it looks like it goes somewhere between the battery and engine but I ran out of day light before I could find it.

My question(s). Where does this tube/pipe go? How much work is it to change it out? It looks like both tubes/pipe go to the same place, and are connected to some of the same brackets together, so I am assuming they come as a set. Im also assuming that the sensor is still good, and the fact that this tube/pipe is broken is the reason Im getting the codes.

Please Help


----------



## MRO1791 (Sep 2, 2016)

OK, these ultimately connect one to each side of the DPF, one upstream, one downstream. It is really hard to trace given very limited clearance. I had codes on mine too, but not a broken line, I did however blow the soot out of mine and used a small amount of throttle body cleaner. I also found the intake pretty caked up with soot, and did my best to clean that at the same time, using some throttle body cleaner, and lots of compressed air, big chunks of soot and carbon flying all over the place! I did not have to replace that sensor, and the codes have not returned. It appears the soot build-up was the issue in my case.


----------



## MRO1791 (Sep 2, 2016)

Oh, I would expect it to be a real PITA to replace these, and I'd expect some crazy stupid high price for these lines.. unfortunately. I would look at a way to repair that line, perhaps an inner sleeve? Given it is next to that bracket it makes an exterior repair more difficult. Another option.. do a DPF delete and then you wont need the DPF differential sensor at all. The interference removal to get to that is going to be pretty extensive. Do you have any ideas on how it came to be broken off like that? Did you have a service done somewhere where they did that during an oil change? It's not too far removed from the oil filter.


----------



## TyGeR (Oct 24, 2016)

MRO1791 said:


> Oh, I would expect it to be a real PITA to replace these, and I'd expect some crazy stupid high price for these lines.. unfortunately. I would look at a way to repair that line, perhaps an inner sleeve? Given it is next to that bracket it makes an exterior repair more difficult. Another option.. do a DPF delete and then you wont need the DPF differential sensor at all. The interference removal to get to that is going to be pretty extensive. Do you have any ideas on how it came to be broken off like that? Did you have a service done somewhere where they did that during an oil change? It's not too far removed from the oil filter.


Im assuming it will be a PITA to fix it with a replacement part as well. Im thinking of cutting it behind the bracket and just adding a hose from there to the sensor. The last 4 inchs or so is hose anyway, I dont see why I cant add another 10 inches. I'd route it away from the rear of the engine to keep away from heat, but its my wifes car so im trying to do it right.

I have no idea how it broke. I had to replace the alternator a little over a year ago, only thing I can think of is I might have done it somehow doing that. No major work has been done on the car while we've owned it. I do get my oil changed at the dealer (free oil change for life when I bought the car). Im guessing something could have happen there.



Spent about an hour on the phone with a parts guy at the local chevy dealer. Exhaust Pressure Sensor Pipe. There are two different ones. One listed as a short (Part# 55586319) And a long Double L (Part# 12654555). The double L sounds like the one I need. $130ish from the dealer with a wait time of 5-7 days. Found it online for around $80. I think I will do the rubber hose to the sensor and see how that does for awhile and keep working thru the codes I have, and if that takes care of it I might order the park and replace the whole thing.

Its part #14 in the diagram I found


----------



## MRO1791 (Sep 2, 2016)

Since it is near the sensor, and on the back side of the engine, a bit more rubber hose is unlikely to be a problem. The pipe is almost certainly as long as it is and stainless, due to the 1200F plus EGTs associated with the DPF during a regeneration event. That is why that sensor is as far away as it is, on the other side of the engine from the DPF. I think making the hose a TAD longer is a good way forward. The cost of the part, even at $80 is a bit high given what it is, but the labor of installing it will be the big effort.


----------



## TyGeR (Oct 24, 2016)

I read over the post about the DPF delete, its something to think about. My wife is having problems with the car feeling like its jerking or lunging when running 40mph to 65mph and not under any load. As soon as you give it any pedal it clears up and runs fine. and if its running high way speeds 70/80mph it runs fine. only seems to be in that low to med speed range when the engine is not under any (or very little) load. We can be driving 45 and its lunging but as soon as we start to pull up a hill it stops. Thats where all this started. I wanted to clean up all the codes and make sure none of this stuff is an issue (I dont think it is) and work toward fixing that issue. But the car has been doing this since around 30k miles and its at 130k now. Dealer ship could never find any issues with it. But, sometimes it will do it and other times its does not. We're going on vacation this weekend so next week when I have more time off I'll run the hose.

Thank you for your input and info


----------



## MRO1791 (Sep 2, 2016)

Ok, well I think I can help. The light engine load surging is a common symptom during regen. Now the diff sensor having a broken line would likely cause more frequent regens. Add to that, my Gen 1 at about 50K started doing the surge more severe than normal I got the DPF diff sensor code. I ended up disconnecting the sensor, blew out the lines, and cleaned the carbon chunks out of the throttle body (well, intake post intercooler, technically not a throttle body on a turbo diesel). Anyhow the cleaning, and post clean forced regen did the trick. (I can command a regen using the Torque App and Bi-scan for GM). I don't think you would have to force a regen, but it would advise the cleaning of the that intake. It's going to be heavily crusted in charcoal like chunks for sure. That restricts air flow and I would have to guess it contributes to the surging. The light load has minimal turbo boost, which seems that restriction would be more of an issue.


----------



## TyGeR (Oct 24, 2016)

That's a lot of good info. cleaning the throttle body as area is on my list of things to do. was going to do it when I go the timing belt (that's overdue) but seems everytime I set aside some money for the timing belt something happens that I have to use it for. 

The surging durning a regen cycle would explain a lot but is super annoying to deal with when driving. it constantly feels like the transmission is slipping and my wife complains about it. I'll get this tube fixed on my next off days and see how it works from there. 

Thank you again for the help and info.


----------



## TyGeR (Oct 24, 2016)

UPDATE:
I did cut the broken pipe behind the bracket just before the 90 and attacked a hose from there to the sensor. The car drives a lot better and doesn't seem to be jerking (the regen cycle) on each drive. This with swapping out some other sensors seem to have cleared up all the codes but one. P20E4. I cleared it out and it came back and its listed as both Confirmed and Permanent on my OBD reader, not sure why its showing Permanent. Im thinking I will give it a week or two just to see if it clears up on its own or at least changes from Permanent.


----------



## MRO1791 (Sep 2, 2016)

TyGeR said:


> UPDATE:
> I did cut the broken pipe behind the bracket just before the 90 and attacked a hose from there to the sensor. The car drives a lot better and doesn't seem to be jerking (the regen cycle) on each drive. This with swapping out some other sensors seem to have cleared up all the codes but one. P20E4. I cleared it out and it came back and its listed as both Confirmed and Permanent on my OBD reader, not sure why its showing Permanent. Im thinking I will give it a week or two just to see if it clears up on its own or at least changes from Permanent.


that P20E4 is an EGT sensor issue, and likely unrelated to the DPF D/P sensor issue. You might want to replace the possible bad temp sensor, or at least pull it and clean it, as the soot could be causing it difficulty in getting a proper read. It might be a good idea to just replace the sensor, it is common for them to die. 









P20E4 Exhaust Gas Temperature Sensor CEL


Im having the same P20E4 code along with a few other Exhaust sensor codes. I was able to find that the Dorman 904-782 is also a replacement part for the 55581035. And yes the 55581035 is the AC Delco part number. I know this is an old post but the part number might be helpful for someone.




www.cruzetalk.com


----------



## MRO1791 (Sep 2, 2016)

Check this out, Amazon has the sensor for less than $60. https://smile.amazon.com/Dorman-904...an+904-782&qid=1566336485&s=automotive&sr=1-1


----------



## MRO1791 (Sep 2, 2016)

TyGeR said:


> That's a lot of good info. cleaning the throttle body as area is on my list of things to do. was going to do it when I go the timing belt (that's overdue) but seems everytime I set aside some money for the timing belt something happens that I have to use it for.
> 
> The surging durning a regen cycle would explain a lot but is super annoying to deal with when driving. it constantly feels like the transmission is slipping and my wife complains about it. I'll get this tube fixed on my next off days and see how it works from there.
> 
> Thank you again for the help and info.


I guess i missed making a comment on overdue timing belt. Figure out how to do that ASAP. That thing will not go long past the service interval, and if it fails you will lose the engine, and that is a total loss on the car, without a doubt. It is not worth the risk to stretch out the timing belt and gamble with that risk. IDParts has a nice kit, but you might be able to part it out on Amazon or Rock Auto a bit cheaper. The kit is nice as it has all the needed items to do the job. When mine is due, it will be done on or slightly ahead of schedule, I will not be taking that risk.. thankfully the Gen 2 has a chain, and I won't need to do it for those 3 cars!


----------



## TyGeR (Oct 24, 2016)

Yes, I need to get it done. Its first thing on my list to do after I sale my mustang. thank you for the parts site. cheapest place I've seen the kit.


----------



## pfw_dfw (Sep 13, 2018)

Ok, It might be that the DPF has a bad Differential Pressure Sensor.

Where is this beastie? Anyone have any pics of the location? Overall view then detail view?


----------

