ALL OBDII DTC code definitions follow the rules, and its easy to determine which system its in, when a DTC rises. the DTC itself will tell in which system it is, if you have an idea.
Body System Groupings
B0XXX ISO/SAE controlled
B1XXX Manufacturer Controlled
B2XXX Manufacturer Controlled
B3XXX Reserved by Document
Chassis System Groupings
C0XXX ISO/SAE Controlled
C1XXX Manufacturer Controlled
C2XXX Manufacturer Controlled
C3XXX Reserved by Document
Powertrain System Groupings
P0XXX ISO/SAE controlled
P00XX Fuel and Air Metering and Auxiliary Emission Controls
P01XX Fuel and Air Metering
P02XX Fuel and Air Metering
P03XX Ignition System or Misfire
P04XX Auxiliary Emission Controls
P05XX Vehicle Speed, Idle Control, and Auxiliary Inputs
P06XX Computer and Auxiliary Outputs
P07XX Transmission
P08XX Transmission
P09XX Transmission
P0AXX Hybrid Propulsion
P0BXX Reserved by Document
P0CXX Reserved by Document
P0DXX Reserved by Document
P0EXX Reserved by Document
P0FXX Reserved by Document
P1XXX manufacturer control
P10XX Manufacturer Controlled Fuel and Air Metering and Auxiliary Emission Controls
P11XX Manufacturer Controlled Fuel and Air Metering
P12XX Manufacturer Controlled Fuel and Air Metering
P13XX Manufacturer Controlled Ignition System or Misfire
P14XX Manufacturer Controlled Auxiliary Emission Controls
P15XX Manufacturer Controlled Vehicle Speed, Idle Control, and Auxiliary Inputs
P16XX Manufacturer Controlled Computer and Auxiliary Outputs
P17XX Manufacturer Controlled Transmission
P18XX Manufacturer Controlled Transmission
P19XX Manufacturer Controlled Transmission
P2XXX ISO/SAE controlled
P20XX Fuel and Air Metering and Auxiliary Emission Controls
P21XX Fuel and Air Metering and Auxiliary Emission Controls
P22XX Fuel and Air Metering and Auxiliary Emission Controls
P23XX Ignition System or Misfire
P24XX Auxiliary Emission Controls
P25XX Auxiliary Inputs
P26XX Computer and Auxiliary Outputs
P27XX Transmission
P28XX ISO/SAE Reserved
P2AXX Fuel and Air Metering and Auxiliary Emission Controls
P3XXX Manufacturer Controlled and ISO/SAE Reserved
P30XX Fuel and Air Metering and Auxiliary Emission Controls
P31XX Fuel and Air Metering and Auxiliary Emission Controls
P32XX Fuel and Air Metering and Auxiliary Emission Controls
P33XX Ignition System or Misfire
P34XX Cylinder Deactivation
P35XX ISO/SAE Reserved
P36XX ISO/SAE Reserved
P37XX ISO/SAE Reserved
P38XX ISO/SAE Reserved
P39XX ISO/SAE Reserved
Network Groupings
U0XXX ISO/SAE Controlled
U00XX Network Electrical
U01XX Network Communication
U02XX Network Communication
U03XX Network Software
U04XX Network Data
U1XXX Manufacturer Controlled
U2XXX Manufacturer Controlled
U3XXX Reserved
Leslie