When I plug in my tech1 scanner my engine coolant is reading is 115 degrees Fahrenheit when the engine is cold (160 degree tstat). It goes up to 246 degrees when the engine is warmed up. Guage is reading normal. Went through the service manual and did all the tests. even with the sensor unplugged I still get the readings above. Manual says I should have 5 volts at sensor connector but I only have 4 volts. Could this cause a no start issue? Manual says fuel will be cut back if operating tempature is too high? But at 119 it should work.It says it should drop to 0 degrees when I unplug sensor but it is not dropping. (yes I am testing the right sensor). any help appreciated. Bad ECM?

 

When you say "Gauge reading is normal" that does call into question if your at the correct sender , because the gauge sender isn't involved with the ECM , which has it's own sender separate from the gauge .

 

Definitely have the right coolant sensor on the front of the block. It's the one that goes directly to the ecm. Tech 1 still shows a reading even with it unplugged. Manual says it should go to 0.Also only getting 4 volts to it instead of 5. Wondering if their is a problem with ecm. after doing the troubleshoot from the manual it seems to lead to that.