For a code reader, I would think you need something like this: Nexas Heavy Duty Truck Scan Tool NL102 Plus ......
I got one of those couple years ago based on several recommendations.
I would think those are more capable in diagnostics and clearing codes than just a Scan D. But the Scan D is on my X-mas list for the kids too as an alternate way to monitor engine status.
I don't however like the Nexas combo 6-pin & 9-pin adapter. it is so heavy that I thought it would tear the diagnostic port off the firewall without a bungee or something to support it. I don't know, they might all be that way.
2004 Holiday Rambler Imperial 40PKD, Cummins ISL 400
2019 Buick Envision AWD