I started having problems with my accord's auto tranny not shifting in D4/the light staying on D4 and having to shift manually through the gears so as not to damage the clutch. After looking/asking questions for a while, I found out that it was probably the Transmission Control Module/Unit (TCM/TCU). I've found that the part is over $500 new and am going to replace through used parts but am not sure where the module is at. Is it the unit just below the shifter or where is it at?