does your scanner dig into all modules on your vehicle? your truck has control modules for
1 Engine
2 Transmission and 4x4
3 HVAC
4 body (locks, windows, lights etc)
5 Security
6 ABS/VSC
regular low cost DIY obd scanners only interrogate the engine control module - you need a much more deep level scan too which are not in cheap price range. Take it to a workshop who are not "kabuli part lagao aur namaz parho" type - but people who are actually knowledgeable.