OK - I have read many posts about code p1281, and have a question. I put a 180 thermostat in my truck and was intermittently getting a p1281 - maybe once a week or so. It started happening more frequently and I got curious. I started hooking my scanner up to it while driving (and using freeze-frame data) and found thatwhen it set the code, the temp was at only 175 degrees. I'm pretty sure it has to be at 176 degrees within 20 minutes - so you can see how close it was. I reasoned that maybe the temp sensor was reading a little off - so I put a new one in. Great - now it sets the code at 174 degrees. With the old temp sensor my thermostat was opening at almost exactly 180 degrees and when it opened the temp would start going back down. With the new temp sensor - nowthe t-stat opens at a 176 degrees reading on my scanner. So - it appears that the new temp sensor reads lower than the old one. Any ideas ? - other than to keep trying new and different temp sensors until maybe I find one that reads a little hotter. Or switching back to a 192 thermostat - don't really want to do that. Might not seem like a huge problem - but in my never-ending quest of making my truck perfect . . . . Sorry this is so long but this has got me stumped.

 

It could be just a crappy thermostat. Most of the ones out there are junk the quality is very very poor. I took my 180 out because it never opened at the same temperature twice. Temp guage was all over the place. I finally got fed up and put in the original 195 that it came with. 10 yrs old and the temp is much more stable. I notice no difference in performance and MPG is actually a bit better.

 

Thanks - I'm probably going to replace the thermostat again. Anyone have any ideas on what thermostats are better than others?

 

Thermostat brands ? Anyone ?

 

Just buy one from the store and boil it in water and check the temp of the waterwith a cooking thermometer when it pops open. You'll get a pretty good idea if it's junk or not, take it back and try a new brand if it doesn't work well. I'm pretty sure a 6.99 part doesn't get an overly rigorous field test.

I just picked upa generic one at Oreilly autoparts and it works just fine. I hadheard that the Hypertech t-stats had sticking issues a while ago, don't know if they ever fixed that or not.

 

stant is a damn good t stat just put the OEM temp in 195.

 

180* - - - - - 195* - - - - - the eternal question.

 

Just to finish this. I bought a Stant Super-stat (180*) and before I put it in I checked both t-stats : old one and new one. The old one did start opening up at about 165-170* and the Stant opened at 180*. Put it in and seem to have fixed my problem. Good call by rabbler (about bad t-stat : even though it was only a couple of thousand miles old) and aim4 (check before installing). I appreciate the insight. I had always just installed t-stats without thinking about it and assuming they opened at the correct temp. Maybe I just never owned a vehicle that was so precise about temps. Thanks again.

 

I never used to worry either but now there is so much off shore and rebranding of parts it's hard to get quality. Price sometimes is no guarantee. The last thermostat I got was plain junk as I mentioned, (can't remember name on the box) but it was made in Israel of all places!???