So this week I have been using my new AE scantool to try and figgure out my low power problems and I noticed that my coolant temp was reading way off. On a warm engine driving through town it was showing temps in the 250's and once on the highway it climbed all the way to 280+, but the factory gauge showed no problems. I went and got a new sensor from Advance Auto and now the dash gauge doesnt work and the AE is either showing full scale at 300* or some other random temp. Is there another sensor that the ECU uses?

 

The AE will not accurately read engine coolant temps on an automatic trans truck. I saw some very weird numbers on mine when trying to read that parameter too. EOT will be very close to what the coolant temp is and is commonly used to determine engine temp. If the gauge isn't working, take the sensor back and either put the old one back, or get a new Motorcraft/Ford one.

 

+2 oin getting a Motorcraft sensor!! I bought one from Advanced Auto parts and the plug wasn't even the same-I don't know if there are more than 1 version such as early '99 and late '99-up (mine is late '99) and it wouldn't plug into my wireing....