Can someone tell me why when I check the resistence to ground through any of the engine sensor ground wires it reads around 20 ohms. This seems a little high. It only does it with the key on, once I turn the key off it goes back to zero. It is a 1227730 ecm running a 2.8L V6.Thanks

 

The voltage drop is affecting the ohms reading.

Put the DVM on a low DC volt scale and do the same. During key on it will show the actual voltage drop through the wire.

RBob.