Have a 96 –850 (157k) non-turbo without tracks fwd sedan, which has an ABS light on. The problem has been intermittent ABS light (on or off) turns on ALWAYS when I start the car, never come on during the time the car is running. If the ABS light does not come on when I start the car it will be off till I turn the engine off. Then goes on with the next restart even I restart the car in a couple of minutes. Never go off or on while I am driving. It is eider on or off. While I am driving or applying the brakes lightly and wiggling the key does not turn off the ABS lights.
My odometer works fine(if they are related some way). I do have an OBD II reader but it will not do the ABS. It may be needed a special one?

Question is:
How I can be sure it is the module and not something else (sensors or pump or simple electrical connector)?
I have cleaned the wheels sensors and checked connections but I do not know what else I can do before conclude I have a failing ABS module resulting in the abs light coming on. I understand the pump failures are rare and they are leaking seals when this happened.