Tranny temp @ -39*C ??

Balls McGee · Apr 30, 2009

Hey guys n gals... new to the site... I put my 98 XJ on a scanner the other night and noticed something weird... it stated my tranny fluid temp to be at -39*C. So I guess my first question before I ask anything else - is there an actual temp sensor that monitors tranny fluid temp? If so then is this a common thing or is it basically telling me it's toast and I need a new sensor? To my knowledge, this sensor is not stand alone and one of the valve body solenoids contains this sensor and must be purchased as a whole. This being said, there are three sensors and I need to know which one it actually is. Or, if I'm wrong all together please correct me

Thanks.

ParadiseXJ · Apr 30, 2009

Unless it's -39*C outside I'd say the sensor is toast.

What's -39*C look like in F, damn that's cold.

asp · Apr 30, 2009

-40 is -40... mathematically they work out to be exactly the same in C or F. i don't know if there's a sensor for that, i don't think there is...

wim hoppenbrouwers · Apr 30, 2009

Hallo. How cold is it now outside in Canada? :laugh3:

ParadiseXJ · Apr 30, 2009

It's a frigid 65*F at 7 am in Northern California, brrrrrrrrrrrrrrr!!

wim hoppenbrouwers · Apr 30, 2009

Brrrrrr. -39C x 1,8 + 32= 102 F. Brrrrrrr:shiver:

Balls McGee · Apr 30, 2009

LOL we rarely see that temp here even in the winter although it's not unheard of with a good windchill factor.

I tested it when it was +15C which I believe is around 60-65F.

So does anyone know if the XJ in 98 even had that type of sensor?

winterbeater · Apr 30, 2009

I looked in the FSM, while all you guys were joking around. In the text is says that the TCM considers the fluid temp when activating the TC lockup. But looking through the rest of the information, there is no temp sensor shown in any assembly, no torques for fasteners for a temp sensor, and no voltage or any other spec given for it. From that, I would have to say there is none. The only other place I can think to look is the dealer parts breakdown, but all the other sensors, like the speed sensors have torques and are shown in assemblies.

Balls McGee · Apr 30, 2009

Hmmm you could very well be correct as most the info I am seeing online (regarding tranny temp sensors) seems to apply more to the Grands and TJ/YJ line.

Did these two Jeep brands when equipped with the 4.0 use a different tranny then the AW4?

lazyxj · Apr 30, 2009

winterbeater said:
I looked in the FSM, while all you guys were joking around. In the text is says that the TCM considers the fluid temp when activating the TC lockup. But looking through the rest of the information, there is no temp sensor shown in any assembly, no torques for fasteners for a temp sensor, and no voltage or any other spec given for it.

[FONT=&quot]I just checked a 2000 FSM and the wiring diagrams do not show a transmission temperature sender.
If the TCM considers fluid temp for TC lockup, it probably is using the water temp sensor as a reference since the transmission cooler is located in the radiator and the coolant warms the ATF.
I would ignore the scanner readout for trans temp. It's trying to read something that does not exist.
BTW, I use a ScanGauge in my XJ and when set in trans temp mode, it shows nothing. Wish it did.
http://www.scangauge.com/[/FONT]

bigalpha · Apr 30, 2009

asp387 said:
-40 is -40... mathematically they work out to be exactly the same in C or F.

Whaaaaaaaaaaat? SPOBI. :moon:

Balls McGee · Apr 30, 2009

lazyxj said:
[FONT=&quot]I just checked a 2000 FSM and the wiring diagrams do not show a transmission temperature sender.[/FONT]
[FONT=&quot]If the TCM considers fluid temp for TC lockup, it probably is using the water temp sensor as a reference since the transmission cooler is located in the radiator and the coolant warms the ATF.[/FONT]
[FONT=&quot]I would ignore the scanner readout for trans temp. It's trying to read something that does not exist.[/FONT]
[FONT=&quot]BTW, I use a ScanGauge in my XJ and when set in trans temp mode, it shows nothing. Wish it did.[/FONT]
[FONT=&quot]http://www.scangauge.com/[/FONT]

I checked out that mini scanner.... that's pretty cool.... kinda like a GTech with a multi-functional scanner built in... nice.

lazyxj · Apr 30, 2009

Balls McGee said:
I checked out that mini scanner.... that's pretty cool.... kinda like a GTech with a multi-functional scanner built in... nice.

I originally bought it to monitor our motor home's water and transmission temps. I got an extra cord so it can be quickly moved between the XJ and MH. It mounted with a velcro strip.
It's a handy device as it can monitor almost everything on the OBDII bus.
It reads and clears CEL codes too.

fireball2889 · Jun 12, 2009

look on ur trans cooling lines or on that side i just swapped my 97 harness with a 99 and there is an extra connector that should go to a temp sender but its on that side of the tranny

Tranny temp @ -39*C ??

Balls McGee

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ParadiseXJ

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asp

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wim hoppenbrouwers

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ParadiseXJ

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wim hoppenbrouwers

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Balls McGee

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winterbeater

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Balls McGee

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lazyxj

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bigalpha

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Balls McGee

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