Mechanical systems
Reference overviews of aftertreatment, transmission, braking, electrical sensing, and cooling—then jump to the related fault codes.
Aftertreatment & emissions systems
DPF, SCR, DEF, NOx probes, EGR, and EVAP on one exhaust story.
Open system page · 20 codes
Transmission control & ratio monitoring
TCM shifting, ratio checks, and limp-mode messenger logic.
Open system page · 2 codes
Braking systems: air and hydraulic
Air-brake supply chains vs hydraulic circuits—two technologies, one safety mindset.
Open system page
Electrical sensing & powertrain inputs
Sensors, heaters, supply voltage, CMP, rail pressure, and boost paths.
Open system page · 14 codes
Engine cooling & overheat protection
Coolant paths, level probes, thermostat regulation, and shutdown logic.
Open system page · 4 codes