Agriculture Tractors Diagnostic Equipment Recommentantions

Hi fellow AP members.

Need to find a good but not expensive multi diagnostic tool for agriculture tractors such as John Deere, New Holland, Case,etc mainly to verify if any major issues with engine prior to remapping in order to avoid any complaints about remap damaging tractor.

Kindly advise if any such multi tractor brand exists as I need to get one to search for existing error codes prior to remapping.

Any advice is more than welcome.

Cheers.