I would try getting codes.

If you turn the key on then off on then off then on usually the codes will display in the odometer. if not see if you can borrow a code reader.

2003 Dodge 3500 Diesel

1964 Plymouth Savoy White 2dr sdn. 512 stroked, Dominator, New Best 9.75 @ 138.50mph
2019 Challenger Scat Pack 1320 White Knuckle-K&N Cold air filter, Billit Oil catch can, drag radials stock 11.911 @ 114mph