The 928S4, 928GT and 928GTS models use a Bosch EZK for ignition and a Bosch LH ecu for fuel injection.

The table below lists the different versions that exist and the Eprom software you find inside.

 
    PORSCHE BOSCH BOSCH DIAG Feature   PORSCHE BOSCH BOSCH DIAG Feature
  Year Porsche LH number Eprom number Bosch label     Porsche EZK number Eprom number Bosch Label  
928S4               0.227.400.035? 2.227.355.334 ? unsure
  1987 928.618.123.10 0.280.002.504 0.287.355.352 unsure if it has DIA   928.618.124.10 0.227.400.035 0.227.355.480 non DIA?
  1987 928.618.123.10  0.280.002.504 2.287.355.832 DIA   928.618.124.11 0.227.400.035 2.227.355.480 DIA
1988 928.618.123.11 0.280.002.504 2.287.355.447 DIA   928.618.124.11/12/14 0.227.400.035 2.227.355.520 DIA
  1989 928.618.123.13 0.280.002.507 2.287.356.487 DIA   928.618.124.15 0.227.400.154 2.227.355.544 DIA
  1990 928.618.123.13 0.280.002.507 2.287.356.487 DIA   928.618.124.15 0.227.400.154 2.227.355.544 DIA
  1991 928.618.123.25 0.280.002.508 2.287.356.877 DIA   928.618.124.15 0.227.400.154 2.227.355.334 DIA

 

     

   
928GT 1989 928.618.123.14 0.280.002.506 2.287.356 486 DIA   928.618.124.22 0.227.400.164 2 227 355 584 DIA
  1990 928.618.123.14 0.280.002.506 2.287.356 486 DIA   928.618.124.22 0.227.400.164 2 227 355 584 DIA
  1991 928.618.123.26 0.280.002.509 2.287.356.878 DIA   928.618.124.22 0.227.400.164 2 227 355 584 DIA
                     
928 CS/SE 1988 928.618.123.12 0.280.002.506 ? DIA   928.618.124.13 0.227.400.043 ? DIA
1989 928.618.123.14 0.280.002.506 ? DIA   928.618.124.16 0.227.400.043 ? DIA
   

     

   
928 GTS 1992 928.618.123.30 0.280.002.514 2.287.357.477 DIA   928.618.124.30 0.227.400.197 2.227.355.341 DIA
  1993 928.618.123.30 0.280.002.514 2.287.357.477 DIA   928.618.124.30 0.227.400.197 2.227.355.584 DIA
  1994 928.618.123.30 0.280.002.514 2.287.357.477 DIA   928.618.124.30 0.227.400.197 2.227.355.341 DIA
  Data gathered from internet and additional research by Theo Jenniskens