This control unit relay is designed for use with diesel engine preheating systems in specific vehicle models equipped with M47 and N47 D20 engines.It is compatible with the following configurations: - 3 Series (E46) 320d with 100 kW M47 D20 (204D1) engine from 1998/04 to 2001/09 - 3 Series Touring (E46) 320d with 100 kW M47 D20 (204D1) engine from 2000/03 to 2001/09 - 3 Series (E46) 320d with 110 kW M47 D20 (204D4) engine from 2001/09 to 2005/05 - 3 Series Touring (E46) 320d with 110 kW M47 D20 (204D4) engine from 2001/09 to 2005/02 - 3 Series (E46) 318d with 85 kW M47 D20 (204D1) engine from 2001/09 to 2003/03 - 3 Series Touring (E46) 318d with 85 kW M47 D20 (204D1) engine from 2002/10 to 2003/03 - X3 (E83) 2.0d with 110 kW M47 D20 (204D4) engine from 2004/09 to 2007/08 - 3 Series (E90) 320d with 120 kW N47 D20 A, N47 D20 C, or M47 D20 (204D4) engine from 2004/12 to 2011/10 - 3 Series (E46) 318d with 85 kW M47 D20 (204D4) engine from 2003/03 to 2005/02 - 3 Series Touring (E46) 318d with 85 kW M47 D20 (204D4) engine from 2003/03 to 2005/02 - 5 Series (E60) 520d with 120 kW N47 D20 C or M47 D20 (204D4) engine from 2005/09 to 2009/12 - 5 Series Touring (E61) 520d with 120 kW N47 D20 C or M47 D20 (204D4) engine from 2005/04 to 2010/05 - 3 Series Touring (E91) 318d with 90 kW M47 D20 (204D4) engine from 2005/09 to 2007/08 - 3 Series (E90) 320d with 110 kW M47 D20 (204D4) engine from 2004/12 to 2007/09 - 3 Series Touring (E91) 320d with 110 kW M47 D20 (204D4) engine from 2004/12 to 2007/08 - 3 Series (E46) 320d with 95 kW M47 D20 (204D1) engine from 1998/02 to 2001/08 - 1 Series (E87) 118d with 90 kW M47 D20 (204D4) engine from 2004/06 to 2007/02 - 1 Series (E87) 120d with 120 kW N47 D20 A or M47 D20 (204D4) engine from 2004/06 to 2011/06 - 1 Series (E87) 120d with 110 kW M47 D20 (204D4) engine from 2004/06 to 2007/02 The unit functions as a relay for the plug system, supporting cold starts by managing the preheating cycle of the diesel engine.It is designed for proper integration into the engine management system.