Battery Temperature Sensor

Cottontail

Three-De Off-Road
NAXJA Member
I have a 2001 XJ and inside the battery tray is a battery temp sensor. Well, I busted that tray when I rolled the Jeep, so I went to the junkyard and got a different tray out of a 1996 or older model that doesn't have that sensor. Now, when I start the truck and run it, I get a code 1492 and the engine light stays on.

Is there a way to bypass that sensor, or do I just need to go back to the yard and grab either a new sensor or a new tray? I cut the wires on the old sensor and threw it out, not realizing that it would cause engine codes.
 

RCP Phx

New member
Best solution would be to re-install the sensor, you could build a emulator circuit but that's going to require knowing how the circuit works.
 

lawsoncl

New member
The engine computer will reduce the charging current if it thinks the battery is getting hot, so you might have reduced charging right now. Ideally, you should replace the sensor. I think it's a standard NTC type thermistor just like the coolant temp sensor, so substituting a 10-kohm resistor should trick the computer into thinking the battery is around room temperature.
 

techno1154

NAXJA Member
NAXJA Member
My 1996 XJ have one. The previous 1994 did not.

Best to get it replaced. Trying to trick it will not work. The PCM is expecting to see the values change as the engine runs. I tried to substitute the sensor with a resister and the PCM returned an error indicating it did not see a change in value. You could change the tray to one with the hole or you could just drop the sensor somewhere near the battery.
 

Cottontail

Three-De Off-Road
NAXJA Member
I picked up a sensor at the junkyard today for $2.00. I drilled a hole in the tray that I bought the other week and it is reading find and the engine light is off.
 
Top