The check engine light in my '03 lightning came on and the code it is spitting out is P0125 insufficient coolant temperature for closed loop fuel control. What in the heck does that mean, and how do I go about fixing the problem? The truck runs great and I haven't noticed anything weird, so I can't tell if this is even hurting the performance of my truck. Anybody ever get this code before? My Lightning doesn't even get driven all that much cuz it's not my daily driver, so any help understanding this P0125 code would be great.

 

I had the same thing. When we installed the elect fan we changed the thermostat and that seemed to be the problem .We installed another tstat and alls well 2 years later,no reoccurcance.(sp)

 

Sounds like your thermostat might the problem.

 

Mine did the same thing - the thermostat is the issue. What temp of thermostat are you running?

Steve

 

It's just the stock thermostat in there. The truck really doesn't get driven much, so it seems odd that something would be wrong.