Remember the diagnosis switches in the left coat closet

Diag switch in Engineers panel and ??press hold??

According to Sparks 2002 EX class:

+ : Excitation, 16 v to 23 v,
28 v when probe is unplugged

S : Signal,

6VDC or more in air.
2 v or less in fuel

– : Low

Here is the deets from the CMM….pretty confusing:
thermistor fuel level