I have a 2014 Chevy Express 1500 AWD cargo van with about 160,000 miles now. Periodically I get this code. Oftentimes it is after driving several hours on the expressway or if I am towing something. Earlier this year I had an exhaust leak at the flange where the tail pipe connects to the pipe that goes to the catalytic converter. I could not remove the rusted bolts. I eventually fixed the leak by covering it up with a kit and some high temperature jbweld. I have looked in the documentation that I have for this van and it seems that it does not have a PVC valve if that is the issue(EGR). I am going to post the freeze data from my scan tool, and would like to know if something seems obviously wrong from looking at that. I hope that the forum will allow me to do that. If I had an exhaust leak at the flange then maybe there is a small leak at the exhaust manifold affecting the frozen data. This van saw use in Nashville for a while then in Florida. How could the exhaust system have rusted a leak unless it was made with cheap parts.
Maybe if I took the tank off and looked inside.
It says right one your scanner. Fuel pressure 44 psi. I don't have the spec for your engine but I think that needs to be around 55 psi.
Could a leak at the exhaust manifold be intermittent like this?
steel does expand with heat.
So maybe I need to smoke test this again and rule out an exhaust manifold leak?
not a bad idea, and you could test your intake for leaks at the same time (which would also cause lean mixture)
I used MAF cleaning solution for this a while back
and is it giving proper values now? which engine does your van have?
However I saw a small oil leak on my valve cover. .... And it is tripping the code.
Nope. valve cover leaks don't cause codes.
You still haven't addressed the fuel pressure.
DTC Descriptors
DTC P219A
-
Fuel Trim Cylinder Balance Bank 1
DTC P219B
-
Fuel Trim Cylinder Balance Bank 2
Circuit/System Description
The Fuel Trim Cylinder Balance diagnostic detects a rich or lean cylinder to cylinder air/fuel ratio imbalance in each bank. The diagnostic monitors the pre-catalyst heated oxygen sensor (HO2S) signal's frequency and amplitude characteristics by calculating an accumulated voltage over a predetermined sample period. An imbalance is indicated when multiple samples of the accumulated voltage are consistently higher than the desired value.
Defective oxygen sensor/s Burnt - maybe but which one?
DTC P219A is a problem detected in bank 1. So you would be focusing on bank 1. (bank 1 is driver's side)
The upstream O2 sensor (or sensor 1) is the one used for metering fuel. The downstream O2 sensor (sensor 2, after the catalytic converter) is purely for emissions purposes, and irrelevant.
your O2S1B1 value is within range in your photograph, but it would need to be graphed over time to diagnose properly. Fuel trim indicates lean mixture which is consistent.
It is a V8 engine
which V8 engine? There were four different options.
taking this to the dealer when my van was still under warranty and they could not find a problem.
not surprising. Dealers don't want warranty work.
Looking at the freeze frame stft for bank 1 is about 4% and bank 2 3%. So whatever is wrong is affecting both banks.
those numbers are normal. They don't indicate any problem.
more pictures
OK done
It looks like I have o repost all these links again. I must have pasted them in the wrong format.
I just got back from a trip and had this code come in several times. Once I had driven for about 3 hrs on the interstate. I stopped ot refill my tank. Soon after getting back on the interstate the code came back in.. Also on my return trip I stopped at a fast food place, when I restarted the engine and it soon came back in on the interstate.
Found a place where I can post them all at once. They will be there for about 30 days.
https://postimg.cc/gallery/zhJwFhP
I have had other capture data. On one set the stft for bank 1 was positive and for bank 2 it was negative. Is that what P219A means.
Is that what P219A means.
did you go through the troubleshooting in the link I posted?
Causes for this code may include:
Engine vacuum leak (large) - I haven't done a smoke test on this.
Defective oxygen sensor/s Burnt - maybe but which one?
chafed, broken, or disconnected wiring and/or connectors- I haven't noticed any but I have not crawled underneath it.
Engine exhaust- I fixed a leak at the junction of the tailpipe and the downstream end of the catalytic converter. The flange had a missing bolt, the other bolt was broken off at the end, and I could not remove it. Eventually got some high temperature jbweld and some "cloth" to seal this. Some of those exhaust repair kits don't work. I had one that would "blow off" after a week or so.
Read more at: https://www.obd-codes.com/p219a
Copyright OBD-Codes.com
A faulty mass air flow or manifold air pressure sensor- I used MAF cleaning solution for this a while back
Bad fuel pump or clogged fuel filter- I searched the documentation and never found a fuel filter that was replaceable. Maybe if I took the tank off and looked inside. I think that there may be one in there.
Read more at: https://www.obd-codes.com/p219a
Copyright OBD-Codes.com
"The code may actually be more difficult to diagnose if the PCM enters readiness mode at this point, because the code is intermittent. The condition which caused the P219A to be stored may need to worsen before an accurate diagnosis can be made."
It is intermittent in the sense that you usually have to drive it for several hours to get the code to come in.
Could a leak at the exhaust manifold be intermittent like this?
An oxygen sensor could be intermittent or maybe some loose wiring to it or mud on the spot where it reads the outside error. It does not seem that the mud would be intermittent though.
So maybe I need to smoke test this again and rule out an exhaust manifold leak? But how could that be intermittent?
And check for bad/dirty/corroded/loose wire connections. It is not always the oxygen sensor that is bad it seems.
I don't recall seeing a service bulletin on this.
Is the imbalance between banks 1 and banks 2? Or is a STFT of 4% the issue?
Now that I have posted the scan tool data is there anything that is obvious about the problem?
Read more at: https://www.obd-codes.com/p219a
Copyright OBD-Codes.com
Is the imbalance between banks 1 and banks 2? Or is a STFT of 4% the issue?
As the code description says:
If the PCM detects an imbalance in the air to fuel ratio for a particular bank of the engine, a code P219A will be stored and a malfunction indicator lamp (MIL) may be illuminated.
So bank 1 is consistently too rich or too lean.
STFT changes all the time. The engine is making adjustments as load on the engine changes, your accelerator pedal position changes, temperature changes etc. I would pay more attention to LTFT (long term fuel trims). When you add STFT and LTFT together they should be as close to zero as possible.
If you want to learn a learn a little more background about how these things work and how to diagnose, check out these links:
https://carkiller.com/scottykilmer/qa/resources/#post-92731
https://www.aa1car.com/library/what_is_fuel_trim.htm
https://www.youtube.com/watch?v=pIJdCZgEiys
It is a V8 engine and has AWD.
" Fuel pressure 44 psi. I don't have the spec for your engine but I think that needs to be around 55 psi."
I will check to see if I have this info.
The problem would occur more often if I was towing something.
I also remember taking this to the dealer when my van was still under warranty and they could not find a problem.
Maybe a recheck of those bulletins might be a good idea. After 8 years they might have found an issue.
Looking at the freeze frame stft for bank 1 is about 4% and bank 2 3%. So whatever is wrong is affecting both banks.
It is not so large though to generate other codes per the link that you sent me.
A weak fuel pump, and a vacuum leak could affect both.
I made some more progress on this. I had to re-tighten the bolts connecting the catalytic converter to the muffler. Then my noise went back down.
I opened up the engine housing inside the vehicle and ran a smoke test again. I never saw any smoke at my exhaust manifold, but had some where I just mentioned. However I saw a small oil leak on my valve cover. It is so small now that the amount of oil lost is hardly noticed at the dip stick. Previously I had seen signs of this leak, but I thought it was because in changing my oil they had spilled some. Perhaps when towing something there is a higher pressure and more oil leaks out than normal. And it is tripping the code. So I need to fix that and then re-use the scan tool and take some snapshots. I found a couple of useful videos on youtube which show how to do this replacement. I found out that my vehicle is one of the hardest to work on. Everything is so difficult to access. I found that out once when I tried to change my spark plugs. I found a video that perhaps will make that easier. For the difficult ones, he removes the front tires and takes off the mud flaps in the wheel well. Then he uses a long extension to reach the spark plugs that cannot be reached from inside the vehicle.
I replaced the valve cover gasket. While I had it torn apart I put in new spark plugs and ignition wires.
I read somewhere else that a leaky valve cover might trip this P219A code. After more reading about this, it seems a lot of things could trigger this code.
When I had the engine cover off I noticed a rubber hose that seemed worn. It was hard to see where it went, but it seemed to go to some wires under the hood towards the front of the car.. Could wires be running in a hose and not gases or liquids? I took a picture of where it connects to the top passenger side of the 5.3l vortec engine. I have not been able to find out, looking at pictures on the net, what it might do. It is not the valve for recirculating gas fumes. I will attach the picture, and maybe someone will know what it is.
It seems that either I can't post a picture or I don't know how on this BBS. I see no icons to post pictures.
If I find out, I will post it later.
Here is the picture using an external link.
Link: 
?rlkey=i3ujzmdd62u6aqq97k4vrdmci&dl=0
It seems that either I can't post a picture or I don't know how on this BBS.
See the topic "READ THIS FIRST - Forum Guide" near the top of the main page.
I had this code pop up again on a long 14 hr drive/ I think it happened when I was climbing a long hill. Previously I had fixed an exhaust leak at the flange between the muffler and the catalytic converter. I think that I may have a similar leak at the exhaust manifold. This may be causing the short term fuel air ratio (bank 1 sensor 1) to be off by about 3%. When climbing up a hill more horsepower is needed and more air flow. So my theory is that it causes the measured air fuel ratio to be more off and triggers the code. When I arrived at my destination and made some local drives the check engine light eventually went out. So this will have to wait until I can get that looked at. When I replaced the valve cover and spark plugs, I could hardly see the exhaust manifold. It does not seem easy to work on and I think that I would want to use a lift to raise the car up several feet so that I can access it from below. So this will have to wait. I was watching videos on youtube about the exhaust manifold and it seems that this might require a lot of labor and not just accessing it from below,; having to remove the engine cover in the van.