My ecu put out the code for the engine temp sensor. Shouldn't my cel be on?
And would a bad engine temp sensor affect gas mileage because I get maybe 15mpg on the highway.

 

Sometimes the ecu will just illuminate the light for just a few seconds,and then store the code..

Yes it could effect gas mileage iirc...

 

The cel never comes on. Maybe the cel is burned out

 

Maybe?

 

The CEL should illuminate when you turn on the ingnition, but before you hit the start. If not the bulb is burned out.

 

I think your engine could be on fire and the CEL wouldn't go on. The CTS can definitely affect fuel economy, so replace it immediately. Autozone sells a replacement with a warranty for $16 I think.

 

I have had my maxima for 6 years and have yet to see it..

 

Thats funny you said that my 87 max had a injector recall and caught on fire and the cel did not come on.

 

My light never came on either but it gave me the code. I had a bad sensor and connector, make sure your wires are in good shape. I have a VE and my car was guzzling gas has if it was a big boat. I also had power loss in the midrange. Replaced the connector harness and sensor and the car is running like a champ.

 

My temp sensor threw a code (no CEL) and my fans would turn on and off randomly. It also ran rough and the idle surged, but I also had a gunked up IACV. It didn't happen long enough for me to notice poor mpg, but I am sure that was in there, too.

I have had the CEL light turn on, but that was shortly after the JDM install and the ECU turned up a code 5-5. It never ran bad and I did not find anything wrong. It is like a "reverse" CEL.