AT Oil Temp 1 vs AT Oil Temp 2 - OBD2

I have found pretty conclusive information that the “A/T oil temperature No. 2” available from the OBD2 port is the Auto Transmission oil pan, with the sensor in the pan, but there seems to be some conflicting information on what “A/T oil temperature No.1” is.

Does anyone know for sure where the AT1 sensor is and what it is measuring?

thank you

“edit: seems that my initial info was wrong. Read on in thread”

 

I always thought it was the oil coming out of the converter. Other one is pan temp

 

Using a scangaugeii I get these results
TF1 is pan fluid temp
TF2 is torque converter fluid temp

TF2 is the one that fluctuates up and down rapidly with torque converter unlock and lock.

 

Ok. Interesting. That conflicts with some other forum posts I read that said 2 is the pan. Are you sure of these?

 

2 is converter's temp.

 

The scangauge calls the pan temp TF1 and the TC temp TF2. That’s all I know.

I renamed mine to “PAN” and “TQC”

 

Thanks guys. I know I’m just nerding out here, but I would like to be accurate when I name my gauges in OBD Fusion, so I appreciate your answers.

I guess the bigger question would be if there is any way one should react to seeing a distinct difference between the temps. I suppose the most useful thing would be in determine which sensor was faulty if one reading became intermittent.

 

If you’re “exercising” the torque converter you’ll see large fluctuations in the TF2 sensor. The “pan” temp will be a gradual rise up to operating temp. Mine is around 185 unpinned and 168 pinned, truck only.

 

Yeah the one that moves quickly is the Converter. The pan is much slower to change. You will see which is which almost immediately after warming up on a normal drive.

https://www.tacomaworld.com/threads/obd-fusion-tips-and-tricks.590248/

Check out this thread for some more helpful info.

 

In Fusion, dig up SLU solenoid PID. If it’s off (0), the temp 2 is going to rise.
Otherwise, it should be within a few degrees except climbing, towing.
Also , if you are tuned, pay attention in slow traffic.

 

just curious i only have the tf2 one programmed into my scan gauge what are normal temp ranges for the torque converter?

 

What's that solenoid?

 

Controls lock-up and partial lock-up( slipping). When it is Off, no fluid exchange happens and temp goes up. My personal comfort zone was 220° when I played with unlocking in 5th. However, on long idle I saw 210 a few times. I know that some guys who tow saw higher. But I could not find any references that clearly states the upper limit.

On stock, SLU is active starting from 3rd.
I have turned it off in 3rd, but kept stock in 4th. When SLU goes On, you lose 200 rpms while accelerating.
Some tunes have it off in 4th up to some high speeds, which ef you up in slow traffic.

 

Makes sense. SLU must mean solenoid lockup, eh? 220 is when I start to get nervous as well.

 

the normal temperature of the torque converter is about 195°F. The temperature inside the torque converter, while pulling a big load from a standing start, could easily rise above 350°F. You can use INNOVA 5110 https://obd2scannertools.org/innova/5110-review/ model scanner, this scanner also shows you more informative code. That's also growing your curiosity. I think you enjoy that thing.

 

No.1 detects pressure line & No.2 detects cooler line, in the valve body.
No.1 is what most call "the torque converter"; No.2, "the pan". What aftermarket PIDs do with them is beyond me.

Quote from Gears Magazine:
"There are 2 transmission temperature sensors attached to the valve body that have separate duties. Temperature sensor No.1 is used for hydraulic pressure control. This sensor is used to revise the apply pressure to clutches and brakes in the transmission for smooth shift quality. Temperature sensor No.2 is used as a basis for modifying the shift timing control when the transmission fluid temperature is high. It is also used for the ATF temperature warning light. If either temperature sensor fails, shifts to 5th and 6th gears will be prohibited."

From AWR6B45 technical literature:

 

Great information. Thanks.

 

@wiljayhi When using OBD Fusion to check the transmission fluid level the pan fluid temperature (A/T Oil Temperature) should be the one to focus on?

 

Yes, pan temp.