General Information of OBDII (On-Board Diagnostics II) The OBDII system is designed to monitor emission control systems and key engine components by performing either continuous or periodic tests of specific components and vehicle conditions, which will offer three pieces of such valuable information: • Whether the Malfunction Indicator Light (MIL) is commanded “on” or “off ”; • Which, if any, Diagnostic Trouble Codes (DTCs) are stored; • Readiness Monitor status. Diagnostic Trouble Codes (DTCs) DTC Example P0202 SYSTEMS B C P U =Body =Chassis =Powertrain =Network CODE TYPE Generic (SAE):
P0, P2, P34-P39 B0, B3 C0, C3 U0, U3 SUB-SYSTEMS 1 2 3 4 5 =Fuel and Air Metering =Fuel and Air Metering =Ignition System or Engine Misfire =Auxiliary Emission Controls =Vehicle Speed Control and Idle Controls =Computer Output Circuits =Transmission Controls =Transmission Controls Manufacturer Specific: P1, P30-P33 B1, B2 C1, C2 U1, U2 6 7 8 2 IDENTIFYING SPECIFIC Malfunctioning Section of the Systems