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1998-2000 ls400 transmission temperature sensor

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1998-2000 ls400 transmission temperature sensor

Old 05-06-17, 09:34 PM
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YODAONE
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Default 1998-2000 ls400 transmission temperature sensor

The Lexus Shop Manual refers to a transmission temperature sensor...ayone have images and P.N.?

Wondering if perhaps part of transmission valvebody solenoid wiring harness

Some images of Shop Manual of AT-5 Lexus wiring diagram depicting Automatic transmission temperature sensor as resistive component.. Numerous posts on ECT sensor replacement as improving performance...but not much on transmission temperature sensor





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Old 05-06-17, 09:58 PM
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Banshee365
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Step 6 in the shop manual that you posted answers your question.

The A340/A341 is the same way although routed slightly different. I recently bought a new trans harness from Toyota for an A340E and I couldn't believe how cheap it way. It was less than $30.
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Old 05-06-17, 10:10 PM
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For the A650 the p/n for the transmission harness is 82125-30460 and is around $40.
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Old 05-06-17, 10:14 PM
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Originally Posted by Banshee365 View Post
Step 6 in the shop manual that you posted answers your question.

The A340/A341 is the same way although routed slightly different. I recently bought a new trans harness from Toyota for an A340E and I couldn't believe how cheap it way. It was less than $30.
I read your transmission rebuuld post.

The transmission fluid temperature sensor is integral to the transmission solenoid wiring harness?

The dealer is working to sort that out.

Images of sensor anyone?
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Old 05-06-17, 10:21 PM
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Originally Posted by YODAONE View Post
I read your transmission rebuuld post.

The transmission fluid temperature sensor is integral to the transmission solenoid wiring harness?

The dealer is working to sort that out.

Images of sensor anyone?
I haven't been into an A650. I am 90% sure they are the same as the A340/A341 series in this regard. The temp sensor is part of the transmission wiring harness that connect to the solenoids and such. I don't have a photo but it's a roughly 3/4"x1/2"x3/8" plastic box that usually clips into a metal retainer that is held on with one of the valve body bolts.

I've got a wiring harness laying around in the garage if you really want a photo of what the sensor looks like. I can post it tomorrow.
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Old 05-07-17, 04:59 PM
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Originally Posted by Banshee365 View Post
I haven't been into an A650. I am 90% sure they are the same as the A340/A341 series in this regard. The temp sensor is part of the transmission wiring harness that connect to the solenoids and such. I don't have a photo but it's a roughly 3/4"x1/2"x3/8" plastic box that usually clips into a metal retainer that is held on with one of the valve body bolts.

I've got a wiring harness laying around in the garage if you really want a photo of what the sensor looks like. I can post it tomorrow.
Thanks...appreciate any image of the sensor...

Also, can you advise whether the transmission wiring harness (temperature sensor assembly) is somthing that can be replaced with transmission in the car....

It is unclear whether the transmission housing wiring through hole connector has to be removed??...by extracting wiring from outside of transmission, and whether adequate room for disconnecting external mating connector...or if exhaust or shielding is going to interfere... (This does not contemplate whether chassis harness shell is brittle...usually I acquire a new connector shell from dealer before replacing any engine component...)
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Old 05-07-17, 06:52 PM
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Originally Posted by YODAONE View Post
Thanks...appreciate any image of the sensor...

Also, can you advise whether the transmission wiring harness (temperature sensor assembly) is somthing that can be replaced with transmission in the car....

It is unclear whether the transmission housing wiring through hole connector has to be removed??...by extracting wiring from outside of transmission, and whether adequate room for disconnecting external mating connector...or if exhaust or shielding is going to interfere... (This does not contemplate whether chassis harness shell is brittle...usually I acquire a new connector shell from dealer before replacing any engine component...)

Yes, the wiring can be replaced while it's in the car. I have a nice photo of the harness new out of the package in my trans overhaul thread. You can see sort of how it mounts. There is an o-ring and the male connector housing is held to the case by a built in metal bracket with a 10mm head bolt into the case. I have had good luck with the big female connector housing on the engine harness going to the trans. It's a pretty large connector and the lock tab is fairly thick and doesn't break easy. As with all connectors, it helps to push in hard while you are depressing the lock tab. I only replaced mine because I damaged it lifting the trans up and down and it pinched it. You need some decent finger strength to depress the lock tab but it's doable.

I just looked at a UCF21 trans on eBay to see the layout and the trans wiring is in the same spot as the A340 series in the earlier cars. You'll benefit from either a flex ratcheting wrench or flex 1/4" ratchet for the wiring bolt. With the pan off and connector unplugged and unclipped you can drive the harness connector out of the case from the bottom rather than prying from the top. Lube the o-ring on the new harness and it will pop it pretty easy. On the units that I have overhauled the unit had gotten really hot at some point during the failure and all of the plastic in the trans became very brittle. I don't see this on units that are known to be working when pulled. I notice this when removing the connectors on the solenoids. The lock tab is wide and thin and breaks when the unit has gotten really hot. This is why I replaced my harness. The plastic on the solenoids becomes brittle too so it's best to sacrifice the connector tab rather than trying to pull the connector when it's still partially engaged and break the lock tab recess on the solenoid itself.

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