Troublesome onboard computer on 1991 325i

["Rudolf Kruger" <rkruger@xxxxxxxxxx>]

I have a 1991 model 325i with an onboard computer that is not working
properly. Pressing the buttons for speed, consumption or distance
measurement does not work - it goes into the mode but the readings stay
zeroed. If I set the speed limit to say 130kmph, funny enough the gong
works. So it registers speed inside the computer, but does not display the
value. The standard speedometer (and fuel level indicator) works, both using
the sensor on the differential, so I have determined that that is not at
fault. The other functions such as the temperature sensor, date and time
also work. A friend's 325i (1990) has functions to display the version of
software and the amount of fuel in the tank, which mine either does not have
or is also malfunctioning.

Another problem is the if the car is double locked (dead-lock), one can
still unlock the passenger side door and boot, so it seems to be
malfunctioning as well.

Questions:
1) Any ideas on what can be the problem with the computer ?
2) Are the two problem areas perhaps related ?
3) Does anybody have any upgrade software that one can perhaps program into
the old CPU ?
4) Is it maybe old software on a new model ?

I would appreciate some help tremendously !

Rudolf Kruger

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