Figured I'd throw a line out there with this frustrating problem. 2005 Corvette, had the car dyno tuned in July using 2.5 bar OS. I had just installed a Mechman 170A alternator several days prior. While on the dyno, with the tuner sitting in the car doing his thing with HP Tuners, since it's a 2005, he didn't shift to reverse after a pull so electronics stay on, plus the headlights were on auto so they would be on so needless to say it didn't take all that long for the battery to die while he was tuning. He threw a jumper pack in the trunk (where battery is located) and the pack stayed there connected until the tuning session was over. Not sure if it died while writing to the ECU but when I backed the car off the rollers and out of the shop, the DIC in the cluster showed service electrical system. The alternator stopped charging as the volt gauge was reading battery voltage(12.5 ish) I turned the car off, started it back up and the alternator has charged seemingly fine ever since. We loaded the car back on the trailer and came home. Sent the alternator to mechman for testing and they said it worked normally on the bench but that the rectifier was discolored. They replaced the rectifier and sent it back. Put the Mechman back in and sent my father on his way (his car, he lives 350 miles from me, I do all the wrenching on it. He Drove the car about 2,000 miles with no issues except for the damn service charging system message. He just came to visit, I pulled code P0622. I monitor generator F circuit with scan tool and it seems to work consistently and normally. (I don't have a scope to watch waveform but the scan tool graphs duty cycle without interruption.) I checked continuity between F pin at alternator connector and the other end at the ECU connector with .6 ohm That seems fine. Alternator is always putting out 14.6 ish. Battery in trunk always within .2 of that, positive post at fuse box same as battery, HP tuners log of a few drag strip runs shows module voltage 13.8 ish.(aside from one spot in a log where module voltage showed 11.XX volts at idle in the staging lanes and then popped up to 13.8ish.
I'm wondering if the battery going dead while tuning could have damaged something in the ECU. I've been chasing this issue for days on end, and it's frustrating because there seemingly isn't an issue. Thought maybe someone had some insight. Thanks.