The problem with ABS sensors is the resistance isn't super critical, they work by the magnetism created in the coil by the teeth passing it (simplified explanation). The only proper way to test them is to apply an oscilloscope to them and spin the wheel, and compare them to a known good one. I've also seen test procedures involving measuring the voltage generated at a known wheel speed.

Those numbers seem really low though honestly, did a little reading and I'm guessing those are actually KΩ, so the front ones are around 900Ω and the rear is 640Ω?

In which case even a junk meter would be accurate and the odds are pretty good that the sensor is faulty.

I just would hate that you spent a lot of money and effort to track down a sensor only to find that it wasn't the issue.

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1993 300D 2.5L Turbo