Hi, I have a Cat 420F2 that has current fault 4364-2 - N0x conversion efficiency erratic signal. It also has 3 operator inducement events. It is in limp mode due to the operator ignoring the alarm. The service manual says that the in and out sensors are installed in the wrong locations. I know they are right because they were not changed. the manual says to verify locations and run the after treatment system functional test with Cat ET. It would not run the test due to the active fault. I pulled the exhaust apart and noticed a leaking DEF injector. It was almost completely blocked up with hardened DEF. I separated the Dpf and muffler and chiseled it all out and got everything cleaned up. I replaced the DEF injector and the outlet N0x sensor. I got it back together and ran the aftertreatment function test and it passed. The only thing is I still have the 4364 fault as active and the red lights are still on. Do I still have an issue? I thought since it passed the system test everything was fixed and the fault would reset. I assumed that my issue was it not mixing in the exhaust stream correctly due to all the blockage. i tried clearing the fault, but it says it’s protected by a factory password. Our dealer has not been much help. We just spent $12k in hydraulic repairs on it and Really don’t want to send it back to the dealer again. anyone have any thoughts about it?
I've been out of the loop on Cat stuff for a couple years so take anything I say with a grain or 2 of salt. I do remember that after a certain derate level that the dealer has to come and unlock it. I think it may be the same way with emission system faults as well. Factory passwords are so that the owner can't just keep resetting the fault without fixing in.
Do you have access to Cat ET, if so try running the DEF accuracy verification test under diagnostic tests tab
If it got as far as a derate because of the operator ignoring the regen inducement warnings then it will require a dealer version of ET to “unlock” the Event.
I do have ET. I will try that test in the morning.
Ok. I still have an active code of 4364-2 as well. Is it supposed to clear itself out when the fault is fixed? I have followed the troubleshooting procedure in the service manual and everything checks out ok And passes the function check. I have been talking with the tech support from the dealer and they say they would have to run DEF tests that require special tooling And we need to bring it in. We are wanting to avoid that because we just got this machine back from them after being there for 2 months for a hydraulic issue they could not figure out. They threw a bunch of parts at it and resealed a couple of valves. We got a bill for $12grand. Needles to say we are reluctant to take it back, but I get there are a lot of things they are only able to do.
You’ll need some advice from the TIER 4 experts about that.
Can you provide a serial number for machine please?
Have you followed the entire troubleshooting procedure for that code? I noticed a few things that weren’t mentioned, DEF quality % results and whether or not you performed the aftertreatment recovery procedure.
I don’t have the serial number with me. I’ll get it on Monday when I’m back at the shop. The trouble shooting for the code says check to see if the inlet and outlet sensors are in the right location and not swapped. They are in the right location. After verification it says to run the aftertreatment system test. If it does not pass contact dealer support services, and if it passes the system is functioning properly. I’ve run the test 3 times and each time it says it was successful. I drained the tank and refilled it with new DEF. I ran the aftertreatment recovery procedure After I cleaned everything out of the mixing chamber. I also ran the dosing test and had a system pressure of 80.7psi and measured 125ml of fluid. Spec was 105ml - 130ml. I read in the service manual that when running the aftertreatment system test in order to pass the correct temps must be met, proper Def dosing, and correct N0x levels. If those were not right it would stop the test and log a code. Every time it has ran it passed successfully. I talked to the dealer yesterday and he said that code only means the inlet and outlet sensors are swapped and in the wrong locations. They think it’s a dosing issue, but I said if it passes the system test the N0x levels must be within spec. The code says it’s for an erratic signal from the outlet sensor , so I’m wondering if it’s a controller issue
Had a Cat genset do that once. Just put the load bank to it for a while and it cleared up. No idea if that'll work for you or not.
Did I read correctly that you replaced the outlet nox sensor? Can you post the part number you replaced with? Also, if you changed to the most current number, it requires a software update to be compatible with the machine. I have on occasion seen where the machine was not happy with an old part number nox sensor being ran with an updated number sensor. It sounds to me like you are having a software and hardware conflict.
Yes I replaced the outlet sensor. It came in with the 4364.2 code for erratic signal, so I was suspecting the sensor. I will have to check and post the the part number on Monday. I don’t remember it off the top of my head. If it is a software issue, can the update be done with the customer level of ET, or does the dealer need to do that?
I can’t specifically say what “customer” ET will do, if you have the “winflash” tab it may be capable but you would have to have the dealer send the software file. When you first start connecting ET, what version of ET does it say you have?
Customer ET doesn't have Winflash capability, so any upload of new software requires Dealer ET.
The part number for the N0x sensor is 539-0118, The serial # is HWC01645 and My version of ET is 2022c V1.0, and like Nige said it does not have Winflash
Ok, you installed the latest part number of Nox sensor, it may or may not play well with the other sensor, time will tell that one. You will need a software update and since you don’t have winflash, you will either need dealer assistance or someone with dealer ET.
Here's the details of the update that @ahart was referring to. It's obviously a fairly fluid document because it's up to Change 4 already...... As regards the 420F2 ST model it applies to all HWC machines from first built up to S/N 03239, so it includes yours. If you look at the top of Page 8 you find the text "The engine software installed must be one of the part numbers listed in Table 3 or later." What software P/N do you have in the engine ECM right now.?
The engine software is 610-0506. Do you think its best to replace those sensors in pairs, vs. just only replacing the outlet?
That's the latest available for 590-1271/596-1628 mentioned in that document, so according to that the 539-0118 sensor should work OK with the software you have. I'll let @ahart express an opinion regarding whether the sensors can be replaced singly or should be replaced in pairs.
The only thing I’m having trouble understanding is at first it wouldn’t run the aftertreatment system functional test due to active fault code 4364-2, later it completed the test successfully but still had the code. Am I understanding that all correctly? Was there another code prohibiting it from running the test? I don’t see how it could complete that test and still have that code. Doesn’t seem feasible to me.
Yes, it came in with and still has just the one code 4364-2. It would not run the test until after I cleaned out the mixing chamber and replaced the DEF injector and outlet N0x sensor. Once I did those two things it would run the test and passed it 3 separate times. I don’t understand why it would run the test either with that code being current. According to the book, if there was a related fault it will not run the test, and if the system was not functioning properly, it would stop the test and log a code. We have a service tech coming out to look at it. So I’ll post his findings s soon as I know something just in case someone else runs into this issue. Thanks to You and Nige for all your help. It was much appreciated.
Update on the repair.. we had a guy come and look at it and he ran through everything I did. When it all checked out ok he called the dealer and checked on the ECM software like what was mentioned here. They had a newer version available and sent him the file. We updated the software, but still had an active fault. He then read in SIS that when the mixing chamber was clogged up like this one you should run the after treatment recovery procedure 3 times in a row. I ran it, and on the second one the code finally cleared out. I ran it a 3rd and it’s still out. I had only ran it the one time after the repair, and did not see about running it 3 times. I’m guessing the N0x level was just at the boarder line so it passed the system test, but then wasn’t good enough at idle to keep from throwing a code. Thanks everyone for the assistance
Hello guys, I’m a cat tech. The nox sensors are expensive. They don’t actually start sensing until they are above 500F for 2 1/2 mins. It is way easier to do any of these repairs before you get all 3 operator inducement codes. Anway, if anyone needs help in the future hit me up. I’m pretty good at any def system fault concerning cat backhoes. [email protected]
I ran into this code about a year ago on a Roller. It was hard at first to see but through the def injector hole we saw a huge dry def deposits. We took the filter apart and at first it looked like you couldn’t take it apart but once you removed a the heat shields you can see a clamp. Removed clamp to access the mixing chamber and chiseled out DEF. Was unsure if the dpf was clogged further up. Sent dpf to get professional cleaned/baker. Installed dpf. And the recovery procedure would not go through. Since it was a roller machine there was no way to raise the rpms to get it hot enough to regen unless we drove the machine. We had the customer run the machine for a day and the code went away.
You can have the dealer come out and delete the code. As long as the fault isn’t active, they just need a password.