For installations of 1999 - 2006, mechanical throttle body, Gen3 (4.8L - 5.3L - 6.0L) engines using ECMs with service #12200411 or #9354896. Engine codes supported are LR4, LM7, LM4, LQ4 and LQ9. 2003-2006 engines require the factory installed throttle by wire throttle body to be changed to a cable throttle type. Harness includes all connections for fuel injection operation: ECM, TPS, IAC, CTS, IAT, MAF, MAP, Injectors**, Coils, CMP, CKP, Knock, VSS, ISS, 4L60E & 4L80E Transmissions, Front Bank 1 & 2 O2 Sensors. Emissions connections included in harness include: Secondary air pump, Secondary air solenoid, EGR, Canister vent and Canister purge. Harness incorporates its own 8 circuit fuseblock with ignition relays and connection to factory style fuel pump relay.