Odometer Test mode shows no oil pressure

[lonestar]

I couldn't wait to try digital odometer test:
http://www.explorerforum.com/forums/showthread.php?t=15542
but I found some disturbing output in the OIL mode.

in the OIL mode constantly read 000 while running and 255 while not running, although the dummy gage reads pressure as normal.

mode description

Displays the code (0-250) for the oil pressure switch input to the HEC. Oil pressure gauge will indicate present oil pressure. Normal oil pressure (greater than 6psi) will display a value between 000 and 176. A low oil pressure or an inoperative e

[/quote]
one explanation

The oil is 000 because our oil pressure gauges are factory set to read mid-scale. There is a resistor wired to the back of the gauge board wired to a switch (the same one used for a dash without a gauge,just a light) on the engine that will only allow the gauge to drop if the pressure is below 6 psi.

I thought the test mode was reading realtime, bypassing the dummy gage wiring....

Anyone have any thoughts on this.

 

[joefnh]

Same Issue

I tried the same tests on my 03 4x4 4.0L, same results.