PO514 Code
 

I check for codes periodically and usually do not find any. I just checked today since it's been awhile and found it showing PO514, which means (BAT Temperture Sensor Rationality). What actually does this mean, I'm curious because these are the original batteries and they are now 5 years old.Also will this code that's showing go away on it's own or does it have to be removed.


Tony

I heard of that code from the guys in the north. They say it comes and goes every winter. Dosen't really cause a problem. I know for the newer trucks (06'-up) there is a flash that addresses this issue.

If it hasn't set the CEL light, don't worry about it. Heck even if it has, don't worry about it. I have been getting this a few times every winter since I owned mine. I just drive it and it goes away. Seems to happen more often when I use the block heater. Check it again in a few days or a week and it will probably be gone. You can have autozone or someone clear it if it bothers you and you don't have a means to clear it yourself.

Thanks guys for the replies.:cool: [roll]

Tony

usually means 1 of 2 things...comes on because of short trips taken with your truck...when it starts to get cold u take a short trip it warms up, then quickly cools..if you make multiple short trips, it sees up and down voltages setting the code or if it keeps coming on your sensor is junk

my truck has had that code from day one. it doesn't cause any problems.

same here. i still get it every now and then during winter but it hasn't effected anything yet

The rationality code comes on in the winter when you have the block heater plugged in .That causes the coolant temp reading at start up to be higher than the intake air temp reading. The computer recognizes that as an issue with one of the sensors. There is a reflash to update the computer with new information that will eliminate that code, along with some other small issues too.

Are you meaning the word "rationality" as the word that's used in some other code definitions, because I've seen it (that word) used on some other "P" code definitons also and really didn't understand the meaning they wanted to convey, or is it just this specfic code P0514 that is related to plugging in the block heater, because I have not used my block heater at all so far this year. Anyway this is the first time I've ever noticed this code since I purchased the truck new.


Definition:
ra·tion·al·i·ty (rsh-nl-t)
n. pl. ra·tion·al·i·ties
1. The quality or condition of being rational.
2. A rational belief or practice.
3. rationality - the quality of being consistent with or based on logic.


Tony

I get that code every winter after driving for a period of time (like for several hours) when the temperature is 55 degrees or less. I just ignore it.

MikeyB

The term "rationality", used in the description of codes, is there to describe the reasoning behind the code. Like in your case, the ECM compares the reading of the coolant temperature sensor to the reading of the air intake sensor and the ambient air temperature sensor to make sure that they are all close in readings. If they are not, the computer sets this code to tell the technician to look at all of the related sensors and wiring to find the cause. It isn't saying that one or the other is necesarily bad, pre say, but that they aren't matching for an undetermined reason. They are all within specs, just not matching, so it doesn't know which one to set a code for. The reflash basically tells the computer to either disregard the coolant temp reading in temperatures below a certain temp, or not to look at at all and just compare the other sensors instead. Can't say for sure, but they did change the programming to eliminate this code in cold weather when the block heater is used.

Thanks vzdude for the explanation, I'm really trying to avoid any sort of reflash that I can, truck runs great now as it is and I want to keep it that way. I can live with the code and as stated from above it will probably fade away. :cool:

Tony

The ecm takes readings from the coolant, oil, air, and ambient temp sensors on ignition cycle to help decide how to map everything to start your truck, the P0514 usually initiates from a block heater being plugged (but not always) in and the ecm seeing vastly different temps between the associated sensors.

This is just an addition to Vzdude's expaination. The accumulative reflash for this may resolve some underlying issues, however if you are not having any driveability concerns with you truck, then you don't need to worry about it, keep on truckin.


Tim