'98 Tahoe Trouble code P0125

I've been having a problem the past few months with a coolant leak. I took it to a radiator shop and they searched all over with no luck, but i still have to add coolant at least once a month. 2 days ago my SES light came on. I had it scanned today and it returned code P0125. What do I need to do to go about fixing this? I'm assuming the two problems are related, am I wrong? Thanks a ton

For 1999-2001 Tahoe P0125 code is insufficient coolent temperature for closed loop fuel control. Don't have a clue other than its tied into your cooling system. Your engine may be running to cool or hot for proper fuel consumption. Any recent cooling system work ????

For 1999-2001 Tahoe P0125 code is insufficient coolent temperature for closed loop fuel control. Don't have a clue other than its tied into your cooling system. Your engine may be running to cool or hot for proper fuel consumption. Any recent cooling system work ????

I had the radiator flushed during Thanksgiving break (im a student at Auburn University) and thats about it. I went to a radiator shop about a month ago to try to locate my coolant leak but they couldnt find it. I've recently put water into the system instead of anti-freeze. Could mixing in too much water cause this?

I had the radiator flushed during Thanksgiving break (im a student at Auburn University) and thats about it. I went to a radiator shop about a month ago to try to locate my coolant leak but they couldnt find it. I've recently put water into the system instead of anti-freeze. Could mixing in too much water cause this?

I have just started getting the same error code in the last week (P0125) on my 1998 Suburban. I had noticed the faintly sweet smell of antifreeze a couple of times after getting out of the vehicle in a parking lot or something, but did not attribute the smell to MY vehicle. The the "check engine soon" light started coming on last week.

Please post again if you get an answer - I will post again if I get a breakthrough.

You just need to replace the thermostat there is an updated part from GM for this condition

I have just started getting the same error code in the last week (P0125) on my 1998 Suburban. I had noticed the faintly sweet smell of antifreeze a couple of times after getting out of the vehicle in a parking lot or something, but did not attribute the smell to MY vehicle. The the "check engine soon" light started coming on last week.

Please post again if you get an answer - I will post again if I get a breakthrough.


My error has since gone away. I think the problem for me was too much water in the coolant and not enough antifreeze. I had a large antifreeze leak at the time, so as more of it was lost i added antifreeze and not water and the error code went away shortly after. I then finally found the source of the leak (heater control valve), fixed it, and I've been good since. My exhaust does smell a little sweet but im not losing antifreeze like I used, so im not too worried about it.

I could be wrong, but I believe this error doesnt necessarily mean a low coolant level. I think it actually means that the engine cannot warm up to the sufficient operating temperature. Check your coolant mixture and make sure there isnt too much water (should be like a 50/50 mix of water and antifreeze). Hope that helps.

My error has since gone away.....Hope that helps.


Thanks for the quick reply!

Those are some good hints - I appreciate the input.

...will post with results.