P1281 Error Code

DHunt

DHunt

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I got a P1281 error code this weekend. I found a thread telling me it's a engine temp warning probably associated with the thermostat. New thermostat on order. Where are all the codes listed? I have the Chilton, Haynes and Ludel shop manuals and none of them list all the codes.
Also, how does a code get cleared?
 
DHunt said:
I got a P1281 error code this weekend. I found a thread telling me it's a engine temp warning probably associated with the thermostat. New thermostat on order. Where are all the codes listed? I have the Chilton, Haynes and Ludel shop manuals and none of them list all the codes.
Also, how does a code get cleared?
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Here's a fairly complete list of codes... https://www.getahelmet.com/jeeps/tech/codes/

Codes get cleared after the problem that caused it goes away, or by disconnecting the battery's negative lead for 2-3 minutes. But if the problem still exists the code will come back.
 
So the code is for engine not coming up to temperature. The dash gauge comes up to just under the 210 mark. Still probably the thermostat? It's winter here in SoCal, but I wouldn't brag about how cold it is. What is the correct operating temperature the computer is looking for?
 
Perhaps it's taking too long for it to come up to temperature, hard to say. Your engine thermostat must be rated at 195 degrees. Lower temp thermostats like 165 or 180 degree models will usually cause problems. This would be a great choice of thermostat... https://www.amazon.com/dp/B000C7YRNM/?tag=wranglerorg-20

If you decide to buy locally, make sure to avoid any thermostat that claims to be "failsafe". They're not, they tend to get stuck in the open position.
 
DHunt said:
So the code is for engine not coming up to temperature. The dash gauge comes up to just under the 210 mark. Still probably the thermostat? It's winter here in SoCal, but I wouldn't brag about how cold it is. What is the correct operating temperature the computer is looking for?
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The engine should read there, between 190 to 205 when warmed up. Could be a bad sensor I think, more knowledgeable minds can chime in I haven’t had to deal with that except when it’s actually been a bad thermostat (which would not give you a good reading). Actually I remember my JK having that issue and it was a bad sensor on the evap canister. Doesn’t mean the TJ has the same problem at all of course when they did get evap cans (in 2003?) they were different than what my 3.6 had.

Edit: correction, according to @Jerry Bransford operating temp should be close to or at 210, 190 is too low
 
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danof76 said:
The engine should read there, between 190 to 205 when warmed up.
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Reading much below 210 like 190-195 is a clear indication it has either the wrong model thermostat installed or it is defective. Very close or at 210 is the TJ's normal spec'd temperature the computer wants. The factory specified thermostat is a 195 degree model, the engine will run at or very close to 210 with the correct model thermostat installed.
 
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I just got the error this weekend. I've been driving the car with a new radiator and all the fixings since June. Weather is a little cooler now. Should come up to temp with 45 minutes on the freeway with no thermostat I would think.
 
Below is a copy of the page from the manual about the P1281 code, the engine needs to warm up to 176F while driving for 20min after start. The thermostat is the most likely cause, and definitely download a copy of the manual from the link posted above.
 

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  • 2004 TJ SHOP MANUAL-P1281.pdf
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Any issue driving with this error? How can failure to warm up properly cause damage? I certainly want to replace it before it fails completely.
 
How can failure to warm up properly cause damage?
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It really won't cause damage per say it could cause plugs to foul out sooner as the mixture is on the rich side as the vehicles warm up time is longer than designed for. It is an emissions code because the vehicle does not get to operating temperature "quickly" therefore the engine is emitting more bad exhaust gasses for a longer time and the engine is not at peak efficiency.
 
Thanks for the good advice. Plus I found a crack in the hose to the heater, so maybe saved myself some future trouble.
therm.jpg
 
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Just a fyi for anyone who may be digging up this old thread as research- one of the negative effects of your engine not getting up to proper operating temp ( running a lower t-stat or none @ all ) is it does not work as efficiently as it was designed and engineered for. You WILL get decreased gas mileage-- and I mean a significant amount.
 
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A simple (and cheap) way to determine what temp you're running at is to grab a bluetooth OBDII device and the Torque app. On mine, it reads 210-213* once it reaches operating temperature. It does make a big difference in MPG if it never reaches that temp.
 
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Does anyone know if trapped air or too much coolant would cause this issue? I just replaced the temp sensor and have two thermostats on hand, which I swapped out the other day, and I just had the code come on today again.
 
Strazi said:
Does anyone know if trapped air or too much coolant would cause this issue? I just replaced the temp sensor and have two thermostats on hand, which I swapped out the other day, and I just had the code come on today again.
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I'm wondering the same thing after replacing my radiator. I've been told that getting the air out is no easy task and it has to go through three cycles of warm up, cool down.
 
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Actormike said:
I'm wondering the same thing after replacing my radiator. I've been told that getting the air out is no easy task and it has to go through three cycles of warm up, cool down.
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Went through a dealership to get mopar and what do you know, a motorad came in the packaging…

I put in the new thermostat and same issue, only got up to 177 and the upper radiator hose was uncomfortably hot to hold onto at this point. I just don’t get it.

I’m praying there is just trapped air at this point but I doubt it. I’m going to lose my sanity.
 
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