Battery Temp Sensor code.

[Tealdreams]

I'm new to this forum and the Jeep Life but I love It already , I bought a 2002 TJ 3 weeks ago and I'm trying to figure out how to get rid of this code , I have a code reader and I have replaced the battery temp sensor and battery but the check engine light won't go away and it continues to come up with the same code, thanks in advance for any help.

 

[JPNinPA]

Welcome to the board!!!

What is the actual code # and have you reset the codes? I'd what did you do to reset them? Have you inspected the wires to and the connector for the temp sensor?

 

[Jeepergeo]

Under your battery, there is a quarter-sized spring loaded sensor that comes into contact with your battery. Apparently it's there to modulate the charge rate based on battery temperature.

My guess is that you have a short in the wire leading to the sensor. You will need to remove the battery tray and inspect the wire carefully. What happens is that wire gets pinched between the body and battery tray, and creates a short. If you clear the codes, they will come back as soon as the short makes contact with the body again. Once you find the short, repair it and then put the tray back in and install the battery after carefully routing the wire so it does not get pinched. Look for a flat spot on the wire. Go might not be able to see the explsed copper, but it is likely there in the crushed section.

As far as I can tell, you can run with the code without damage to the vehicle, assuming you are not trying to run where the temperature goes sub zero. But I'd fix it and be done with it.

BTW, this exact situation happened on my 2002 Sahara Wrangler, and it has not recoded since then fix a few years ago.

 

[Tealdreams]

P1492 is the code, the temp sensor is new but I did notice that the old one I took out was punched under the tray, I made sure the new one wasn't when I installed it, I'm also getting the proper 5 volts when I check it with volt meter , I'm guessing it's in the connector or in the wire harness somewhere.

 

[JPNinPA]

Was this an aftermarket sensor or from the dealer? I don't know about this particular sensor causing greif but others need to be oem or they just fail.

How did you reset the codes?

 

[Tealdreams]

I bought the sensor from advanced auto , I also tested it to see if it ohms out properly before install and I cleared the code many times with the code reader and also holding the positive and negative together for 20 secs.

 

[Tealdreams]

Could the sensor be tied into something else that I'm not aware of?

 

[JPNinPA]

Perhaps it's working correct and there is something else wrong. What is your battery voltage with engine off and engine at idle?

 

[Tealdreams]

Battery checked out good at idle and off! It's got to be in a connection somewhere, or tied into another ground that might be bad, I know one thing for sure! It's kicking my butt.

 

[JPNinPA]

Battery checked out good at idle and off! It's got to be in a connection somewhere, or tied into another ground that might be bad, I know one thing for sure! It's kicking my butt.

What voltage did you read at each idle and off?

 

[Tealdreams]

12.8 with engine off and 13.8 at idle

 

[JPNinPA]

12.8 with engine off and 13.8 at idle

Off should be 12.6 unless you were just running the engine and shut it down with no load. An additional charge will remain for a few min. Engine running with a load should be 14.4v and 13.8 no load. The battery temp sensor will limit the charging voltage when it senses hot. If you have a bad battery it will get hot when charging. The same will happen when alternator is failing. A $20 IR temp reader will give a good idea of how hot.

Also if you clear the codes and with the the engine cold the battery code pops up immediately.. It's unlikely the battery or alternator.

The battery temp sensor is a thermistor that changes resistance with temp. Perhaps you could verify the res at cold, room temp and elevated temp. (with a hair dryer on it)

Lastly check all your fuses. I'm not sure currently the exact one.

 

[Tealdreams]

I will check the fuses again , all seemed good the last time I checked, I also switched out Batteries with my buddies Jeep to double check that it wasn't the battery and the light comes on as soon as you turn the key. Thanks for trying to help some how I'll get it .