Hi I have a 1999 dodge ram 2500 diesel,automatic transmission,4x4, 430000 km. Basically to sum it up it started with it only high idling intermittently and would get no temp reading got to the point it was every time, so I took it into a shop and they told me the fuel system failed so I switched both the vp44 and put a fass pump on it and still is running around 1100rpm idling and when shifted into gear drops to about 1000 in gear but gives quite the kick. But am also getting no temp reading on my dash at all and have ran a Acura or test on it and all worked. Tried switching the temp sensor and that didn’t do anything. I did scan the truck and it gave p0380 (grid heater circuit relay code) but that’s the only code it’s picking up.

 

Does the PCM know what temp the engine is???

 

I have scanned the truck and there is no coolant reading at all even after letting the truck warm up

 

PCM should have some reading for coolant temp. Even if its -40..

 

Have you tested and/or replaced the coolant temperature sensor or checked the temperature sensor wire for possible breaks?

 

after upgrading my scanner even after running it still reads -45

 

Then something isn't working, either the sensor, the wiring, or the PCM.

 

I ended up putting a new sensor in and have tested the plug going to the sensor and it’s reading 0.70 ohms

 

And what does the computer think engine temp is?

 

it’s still thinking that it’s at -45 even after running and warmed up