ok I am having a problem with my 2003 L200. I keep getting engine code p0171 and the cooling fan kicks on at mega speed when ever the engine is on. I have cleared the code but it comes back after the CAT monitor comes on. I have changed the MAP sensor and the fuel filter. the car ran great for about 40 minutes after that but while watching it with my OBDII reader I see that after the Cat monitor comes online about 20 minutes in to my test drive the code come up soon after. how can I tell if it is my CAT or one of my O2 sensors? Does any one have an idea as to what is wrong? thanks for your help. the L200 has the 4cyl engine.

 

Does your car have any problems accelerating or climbing hills? If it's losing power, then you may have a clogged cat con. If not, just disconnect your battery ground cable for a few minutes and see if that clears the code. As far as the cooling fan kicking on at full speed, you may have a faulty coolant temperature sensor.

 

Don't forget, if you are running your A/C in the recirculate mode, that will cause your cooling fan to run continuously