I have a 96 F150 4x4 4.9L Six 138,000 KM. A couple of weeks ago my check engine came on, engine was running fine. I took it in to the dealer for repair. They tested it & replaced my engine O2 sensor. A couple of days later the check engine line returned, engine was still running ok. Returned to dealer they retested now they got a Catylitic Converter Below Limit error. They said this was because I remove the converter when I replaced the exhaust. I told them the exhaust was replace at 40,000 km & I did not have a problem with my check engine light. There only suggestions they have are to replace the catylitic converter or remove the check engine light blub(which they said can cause problems). Does anyone have any suggestions. Thank you.

RGM

 

There is some sort of reset on the light. Alot of manufacturers seem to have the light go off even when nothing is wrong. Try unplugging the battery for 20-30 min. This should kill the current so when it is plugged back in it will reset itself and run another diagnostic check on itself. I did this when my ABS light wouldn't go out, and sure enough it did a reset then ran another check and the light went out. Hope this hepls probably won't but hey I tried right? Not tryin to be a smart ___ but I am no good at electrical things, and I just thought I would share my "how I fixed it story".

cpnhgnjnky

 

RGM:

I have the same truck. When my light came on I replaced the o2 sensor by the convertor. I unhooked the battery to reset the light. About a week later check engine light came on again. I had to replace both o2 monitors. One is mounted in each manifold. This solved my problem.

Chris