It seems my V12 engine (DBS MY 2011) does not have misfire correction factors saved in the ECM. Over last month my local dealer did full Coast Down Procedure twice (it took 400km in total) without any effect. The profile correction flag is set “Learnt”, however there is no single Misfire Correction Factor stored in the engine modules - AMDS reads no values. I pushed my local dealer to explain that. After consulting with Aston Martin Tech guys, they told me that my engine for sure has learnt, however the correction is not matured (what???), so I need to drive for a while with no faults present when the Misfire Correction Factors will be saved in ECM.

Hmm, technically speaking that sounds incorrect to me. I would appreciate any suggestions/comments? Thanks!

 

If the PID/datalog shows learned, then its as stated..it's learnt (providing 36-1 pid's show learned in Primary and Secondary ECU). Your car is working and detecting misfires as it should.

What most likely is not showing up is the actual values on the AMDS app which can backup/store/restore/erase the misfire correction factors into AMDS.

The reason why you cannot backup a copy to AMDS is a software conflict between your engine module's software and the AMDS. The hex code address(or similar) most likely changed the location of the values stored location, now when the AMDS app goes to retrieve these values, it's reading to far into the coding which see's this area as "zero's"..aka AMDS reads the values as zero and not what they should be. So the AMDS user is prompt with a msg stating "Misfire Correction Not Learnt in ECU/s".

The reason the PID/datalog can read learned and the app to store the values see nothing...that's all related to whats being looked at. The pid is looking at a generic "switch code" (1 or 0) that is OBD2 compliance. The AMDS app to store values is going more in-depth to retrieve values and NOT looking at the switch code function of 1 or 0


How do I know this? "Been there..done that!

If you look at the log file, more than likely your vehicle ecu was saving them to AMDS correctly, but once the software was updated, the tech was able to restore the misfires BUT could no longer save the data to back up onto AMDS.

The only reason the tech tries to backup the data into AMDS is for ease of repair on future date. If your battery goes flat(storage duration over winter), ecu is flashed/updated, the misfire corrections are wiped out. If there's a backup saved, this allows the tech to restore them without the need of putting miles on the car (click of a button and restored values). By not having the ability to restore the values by AMDS, just means that car needs to have the misfire correction drive cycle completed to relearn the values....bear in mind if you changed a clutch or anything else affecting rotating mass, the old values could not be reused because it was for the previous rotating mass, this new values would need to be learned regardless of a backup being available.


Hope this help!

 

Irish, thank you so much for your input. I am so impressed with your expertise. This is exactly as you described. Datalog reads "learnt", misfire counter works fine, however AMDS cannot read misfire correction data for each cylinder from both ECUs. My dealer did an initial PDI of the car, but unfortunately they have not got any historical backup data (????), so they did misfire learning procedure now to fix it.

Indeed, both ECUs were flashed at least twice, so they are fully updated. If there is a conflict between updated AMDS and the new ECU software, do you think there is any way to read and store the misfire data in AMDS? I just cannot understand why AM has not resolved the issue of conflicting software in their own diagnostics system allowing it’s dealers to be confused and puzzled in front of their clients. Thanks!