Mercedes / Bosch Idle Control computer. Mercedes part number 004 545 10 32  W126 leerlaufdrehzahlregelung 412 214 001 001 -From a salvage but running 560SEL. Unit was fully runtested controlled idle properly in an actual car and is warranted for 30 days from purchase date. If you have a faulty unit but your valve works, your car may idle too fast or too slow depending on if it's cold or hot or stall in traffic. Very un Mercedes like... This should fix that! This is over for $300.00 from MB