That many fault codes is implausible.

Purely from a fault finding perspective, it seems to me you have a problem on the CAN bus which links the various modules and sensors controlling the engine.

Did you have an initial problem which made you change the wiring harness?

This is purely a guess, but I think you may have something on the CAN bus (sensor or actuator) which is blocking signals from/to other devices. Not sure how I would progress this, but I might be tempted to disconnect various sensors first and see if the situation improves, as in most cases the ECU will compensate for a missing sensor.

Other more basic things might apply, how good is the battery? is the voltage low?

Good Luck,

Richard

__________________
1989 W124 300E
1991 R129 500SL