See above photo, active faults - 0 I've come across this issue 3 times in 13 years. Was curious if anybody had any insight to what causes it. ECM fail is rare but possibly the cause, machine still works fine all 3 times after repairing the problem, just makes diagnosing take longer. Caterpillar is pretty easy to work on, however it throws you a curve ball when it does the following. Had a wiring issue with a 777 turbo inlet sensor, high resistance on the signal wire resulting in a voltage high scenario, except ET doesn't throw an active code in the bottom left corner "active code" tab. The only way to see that there is an issue is to click the status (red /\/\/ button) and when you go into engine sensors status you can see it says "voltage above normal." Sorted the problem out by voltage drop testing across the signal wire and repaired the bad wire however it took longer then usual as the first thing I did was check supply/ground/pull up at the sensor and everything checked out. I've also had this on a D10T for the park brake solenoid, you could unplug it and it wouldn't throw a fault, however it is visible under status as well The first time I ever saw it was on a impeller clutch pressure sensor on a 994k - also had active fault but not logged on the OBD or on the active code bar, only visible under status on ET. Sorted out the problem all 3 times but it definitely takes longer when you open ET and check codes and it shows the circuit is fine. Tried flashing engine ECM this time, has most up to date software, checked ECM powers and grounds, all good. Anybody come across this before?
How old is your ET?
Some fault codes will only become active when that component is required by the ECM. For example the 994K impeller clutch sensor may only show an active code when the impeller clutch solenoid is commanded on and the ECM needs to know the pressure. ie under reduced rimpull conditions. Also the frequency that the ECM fetches sensor data varies. Some sensors may only be sampled maybe every couple of minutes. I've never really thought about it but I suppose that when ET shows the status screen, it needs to "ping" each sensor so that it can display the values. In that case it would discover the fault.
2025A V1.0 Are you aware if there is a newer version?
Good thoughts, however all 3 times we had an issue with the said circuit. The dozer for example had low brake pressure (200 PSI instead of something like 450 PSI I think the spec was). The solenoid wires were broken underneath wire insulation (they would stretch haha) and when it was demanded on and it still didn't register an active fault under the bottom left tab on ET, only on status. You are correct though, if you applied the park brake, on the status screen the current low fault would go away. I can't quite remember what actual fault we had with the 994, however I believe it was overheating PT. However, rimpull is always used when digging with this machine, and there were no active or logged codes, only the one visible through status menu. In the case of the 777, the issue was it would alarm on monitoring screen on dash for air filter restriction. It was also active level 3 event under the status bar (next to active code/active event tabs) If you went into live graph it said "Air filter restriction ("H20) : 3508B - Unidentified Failure" The issue with your logic I see here is that when you unplugged the left side, it would throw a active code for turbo inlet left side high voltage, but not the right side? Surely they are equally important in the mind of the ECM Have you had this occur before or anything?
The latest ET is 2025B, but the changes from 2025A are minor. I can't say I haven't seen it before, more that I haven't noticed it before. However now that you've brought it to my (our) attention I'll certainly watch out for it in future. Thank you. Yes, I agree. But then, ECM software and ET is made by people just like us and as such can't be perfect by definition. Your best tool is under your hat.
I can recall coming across more than one where we were pondering why no Alarms/Codes/Events for XXX and when the Cat software engineers dug into it they found that the machine software responsible for flagging up the anomaly was looking for an input from a certain sensor on "Channel A" where in actual fact the input was coming into the ECM from said sensor on "Channel B". See the comments above by @Cmark regarding the software being written by humans.
2025C is the current version. I was making sure that you weren’t running like a five year old version. We have seen a LOT of issues from people using older ET versions and a lot more ET glitches and general machine glitches in the past few years. If you are flash updating machines (if you are a dealer mech) and performing calibrations then you want the latest version for sure.