Question about problems with cooling sys

I bought a 97 Ford Explorer XLT 8 cylinder about a week ago. I first noticed I didn't have heat so I had the part store run the computer on it and got the P0125 code....as I figured I replaced the thermostat. Well the temp guage started working after that and I had heat, but when I took it back to the part store I got the P0125 and P0401 codes. Well I decided to go the cheapest route and replace the temp sensor, although I noticed there is another thing by the engine that looks just like it. The manual said it was on the left side by the manifold and that is the one I replaced...well, I still have heat but the temp guage is no longer working again...please help me out here with any suggestions.

Should I replace the other thing that looks like the temp sensor...or what the heck is that thing?

I don't know a whole lot about vehicles but I can usually do minor repairs as stated above. It may not be any help but when I replaced the thermostat it was in pieces so I am guessing it has been broken for some time.

Were the codes erased after you had them read? If not it takes about 50 ignition cycles to clear the code. The P0401 is probably the DPFE sensor for the EGR system. Good luck. If you still have the old sensor, re-install it and see what happens. Then have the codes erased.

Were the codes erased after you had them read? If not it takes about 50 ignition cycles to clear the code. The P0401 is probably the DPFE sensor for the EGR system. Good luck. If you still have the old sensor, re-install it and see what happens. Then have the codes erased.


I don't know how to erase the codes, how do I do that? I still have the sensor and will probably put it back in like you said. Thanks.

Install the old sensor and go back to parts house and have the codes read again. After you get code numbers, ask them to clear the codes for you.