I've seen several posts regarding what ECU "fail" messages mean. In talking to several "experts" I've realized there's a lot of "old wive's tales" developing around this stuff. I'm certainly no expert but just a basic read through of the AFM tells me a lot of the "facts" I have heard from "experts" just can't be right. A particular area that seems obscure is how the FADEC/ECUs do their "failure" logic.
Recently, I received a very interesting and clarifying email from the folks at Premier Florida. It explains that "fail" doesn't necessarily mean "fail" when you see it on the CAS area of the G1000.
Turns out "failures" can really relate to sensors not the ECUs themselves and, sometimes, a single sensor is used by both ECUs. So, when you get an ECU A and ECU B failure that really might mean that one of the sensors have failed or is giving suspect readings. It doesn't necessarily mean that engine is about to give up on you. This article helps make sense of what the real chain of failure likely is and what the corresponding action should be.
i have attached this document. Hope you all find it as interesting as I did.
I've come to consider the "ECU Fail" somewhat equivalent to a "Check Engine" light. You need a special cable and software to get into the details and diagnose the issue. Thanks for posting David's article.
chili4way wrote: ↑Fri Apr 08, 2022 1:27 pm
I've come to consider the "ECU Fail" somewhat equivalent to a "Check Engine" light.
I think that's a great way to think about it. Sometimes it's a sensor problem, sometimes it's a h/w problem, almost never is it a problem with the ECU itself.
We had dual ECU failures on the left engine a couple of weeks ago climbing out of Bremerton. Hooked up the wizard s/w to see what was going on, and it looks like it might be a wastegate actuator problem since boost was getting over the limit. Defintely not something I'd want to be flying around with thinking it was just a sensor problem (there are two; both agreed).
When I first had my plane I had spurious ECU failures which when downloaded said, "CAM SENSOR." Since I got them *in flight,* and this sensor is about watching the cam sensor when starting, the mechanic said it was meaningless. I can't remember what made it go away.
The only other time I had a failure it was a failure of the ECU board.
Colin Summers, PP Multi-Engine IFR, ~3,000hrs colin@mightycheese.com * send email rather than PM http://www.flyingsummers.com
N972RD DA42 G1000 2.0 s/n 42.AC100 (sold!)
N971RD DA40 G1000 s/n 40.508 (traded)
The light is amber colored so indicates "caution" it is unfortunate that the G1000 is labeled fail.
In 15 years I have never seen a genuine ECU failure, by that I mean a computer failure.
They are all sensor fail, damaged harness, or operation outside of set limits.
The Engine Control Unit has always continued to do what it was supposed to do.
One of the two ECUs for my left engine went entirely AWOL. Kept trying to run the engine at some insanely high RPM, outside limits so it counted as a "fail," and it was taken offline and ECU B was used instead. But definitely not a sensor failure and $1,500 to replace the board.
Colin Summers, PP Multi-Engine IFR, ~3,000hrs colin@mightycheese.com * send email rather than PM http://www.flyingsummers.com
N972RD DA42 G1000 2.0 s/n 42.AC100 (sold!)
N971RD DA40 G1000 s/n 40.508 (traded)
Can we as owners remove ECU failure warnings? Majority of these failures are false and our maintenance shop has removed it many times. Unfortunately the shop is not at same airfield as we are. They had a special cable and a software for this.
Can somebody guide me how this can be achieved? I'm running a flight school and we get this false warnings all the times.
Attend the Austro MX course, buy the expensive cable, install the AE Wizard SW, and get a GPU. Not cheap, and you’ll be better equipped to assess if the ECU Fail is material or a nuisance.
I am not a mechanic and attended an online course last year that was presented by Diamond Canada. Since you're in Europe, have a look at this part of the Diamond website and perhaps contact them directly.
It might be helpful to understand the situation when the ECU failures occurred and if these were "latched" or not. I have the impression the ones you experienced were latched and required specific action from your service provider to reset. If so, they should be able to tell you what the error code was and insights into what the ECU didn't like. It would be better to resolve that than have the nuisance of have to regularly connect up the cable and PC.
If your DA40NG has air conditioning and it is operating when you do your "run-up", this can trigger ECU failures. The solution is to open the vent windows before performing the "run-up." I've also seen an ECU fault happen if the "run-up" is attempted before all the engine temperature gauges are in the green. However, neither of these were "latched".
ECU (so called) Fail.pdf
