codes P1258/ P0128

[paintdude96]

last week it got cold as shit here and my Yukon ran hot maybe cause I only had water in it . well I changed the thermostat and put in some antifreeze in it . well this morning on my way to work my CEL came on and so when I got to work this morning I had the guys over at midas check it out and 2 codes came up P1258 & p0128 . is it cause it ran hot and the codes got stored in it . and what temp. Thermostat should I be running in my Yukon SLT 5.3l .

 

[paintdude96]

no body has any info

 

[OR VietVet]

The codes may have set because of the overheating. You didn't say whether the overheat stopped after the thermostat replacement. All detailed info would be nice to have. I would have had the code reader clear the codes and then drive to see if any codes came back, especially if the temp is now normal.

 

[SLCHOE]

As mentioned above, they are overheat codes.

 

[OR VietVet]

I understand that he overheated but he didn't say the codes were because of that. I looked up the codes my self and found they are related to an overheating incident. He then said he replaced the thermostat but did not say if the overheating problem was solved. He did say the codes were pulled because the CEL came on and then he asked if we thought the codes were because it overheated previously. That is how it was presented and then I asked if the overheating had been cured because he did not say one way or the other. I guess I can assume but I don't like to do that. That is why I asked. I then offered that I would have had the code reader clear the codes, he did not say if that was done. Then I said I would have driven the vehicle and see if the codes came back. Again, he has not answered that. So here we are with still unanswered questions to deal with that could help decide where he goes from here. Ball is in his/your court.

 

[paintdude96]

sorry for not given the full store but yes the code reader clear the codes and it has not ran heat since I did the new thermostat. but also what is the recommended thermostat

 

[paintdude96]

any help on what thermostat I should be running in my 2003 yukon5.3L

 

[OR VietVet]

I looked it up and according to OE it should be the 186-187 degree thermostat and should have a bleeder jiggle valve that would be mounted so the valve is at 12 noon when in the housing. That would help bleed any trapped air. You can see the PDF pic if look up the AC Delco thermostat at Rock Auto and click on "Bleeder Jiggle Valves".