We've been going back and forth with these two codes for a while now on the 8210. Intermittently it would set the codes PDO and E998 while on route. The 998 codes states to cycle the key and if that doesn't work then replace the Handle Head (HH). We tried a bunch of things while working with factory but this seems to be the fix or at least something you can rule out before replacing the handle head. After updating the software to the latest version for the HH and the F series amp, we found the FU3 and FU5 fuse holders and caps so close to the front cover that it would inadvertently push the fuses further in and causing them to open for a second and then it would lose the display and set the codes in flashware. All we did was pull the fuse holders out of the bracket and zip tie them to the harness as a test before kicking it back on route for a week and it came back with no codes pdo or 998. Anyways, if you're dealing with these codes, give it a shot.