99xj4.6

ive been looking for a good xj site other than naxja. i have came across here and new i found my place. im new and looking for some help, i took my xj for emissions and got a code p1492. after looking it up i came up with ambient battery temp sensor, what is it where is it and how do i fix it?

i read you can bypass this but no explanation how is this rite if so how thanks

maverickdan

the bts is under the battery in the tray, its a flat circle. you can disconnect it and check it with an ohm meter should be somewhere between 9000 to 11000 not sure how to bypass it though

Eryk

Hello fellow xj owners, I recently got a check engine light and it scanned for P1492. Im going to check the connection for the sensor and go from there. If anyone has found out how to fix this issue Please Repsond And Share!

PS: Would this code cause a no start? Ive been battling a starting issue as well. Starter is new neutral safety switch is new, battery is new, alternator is new (upgraded to grand cherokee alt), cables are all connected.

dave1123

Underneath the battery there is a round plug that you pry up and remove. On the other end of it there is a 2-wire plug. Disconnect the plug and test it for resistance. Don't let the plug slip down under the tray. This sensor tells the PCM when the battery temperature gets too hot, then it reduces the alternator charge rate. Your no-start could be caused by a flat battery or one that's below voltage required for the PCM.

97grand4.0

Yeah the battery temp sensor is actually much more than that.

Without it your monitors won't "complete" meaning you will fail inspection. **I think maybe**>>It also means your mileage will suffer big time because you won't be in closed loop. Chrysler does a great job of burying this information so you'd never know it. Worked around mine with too cold of a resistor years ago, took it in for inspection, they demanded that I had recently disconnected the battery, and told me it fails. Told me drive it on 690 and bring it back, did, and still failed. I was stumped and uninspected for about 2 weeks until I sorted that one out. I bought a scan tool I have now and could see that the monitors were incomplete. Couldn't figure it out for anything. Posted on this forum, still nobody could figure it out. I finally did. It was the resistor I replaced the temp sensor with, it was 'too cold'. Heh.
It's not, however, the direct cause of your no start

Idunno

Zombie thread -

Bringing it here after searching the forum for a possible connection between code P1492 (battery temp sensor) and a coincidental no start condition. I inquired about the no-start condition in another recent thread today that I'm suspecting is because of a failed ignition cylinder lock/tumbler. The respondents to the zombie thread stated that there wasn't a connection between the code and the no-start problem.

That said, I pursued the battery temp sensor and found one wire with insulation worn away on a spot that was obviously pinched. I'm guessing the pinched spot was a short to ground that threw the 1492 code. In any event, should I fix the battery sensor and reattach it or short the frame harness connector with a 10K Ohm resistor? One respondent in the zombie thread stated that the sensor has a resistance between 9 and 11K Ohms so that's where I split the difference with the 10KOhm. How important is that sensor in the overall vehicle operation?

Thanks,

97grand4.0

I have tried the resistor before and it doesn't end well. Much better off doing the open part surgery on the existing sensor. You could try replacing it but here too only Mopar I have had success with and for that matter never really had one go bad. But maybe a junkyard would be another option

Idunno

Yep. Decided that would be how I approach it when it's problematic. I resolved the no-start problem. It wasn't the NSS at all. It was a broken ignition switch pin that sits between the switch and the lock cylinder. The pot metal channel that engages with the rotary ignition switch broke off preventing the switch from rotating to the start position.

https://app.box.com/s/3z7qdw40jnc01bqd356vh30te4de3f9i