Transmission temps... Maestro added, temp is startling

2008 v6 auto Sport with towing package, so it has an oil and transmission cooler. I installed a new head-unit with Maestro data thing. I also replaced all the fluids, including transmission. The readout for my transmission temp has me concerned.

From the research I've done this is pretty high, but there are several places temperature can be taken. The Maestro gets its information from the CAN buss, but not sure where the sensor is. This picture was taken at a stop light - I had been in 5th gear, about 1200 rpm traveling down a city street. Temp outside was 90f.

What do you think?

 

That's really high, have you verified the temp reading is correct by letting it sit overnight and seeing if the temp reading matches ambient temp?

 

No, but I will tomorrow morning. Thanks for the tip.

 

I'm sick to my stomach right now. It just hit me - When I picked it up from the shop today they told me the transmission was overfilled (they replaced a bad gasket on the fill plug). I had changed the fluid last week and thought I'd brought it up to full temp when filling it, but now I bet I didn't. I'd guess between then and now, I've put about a dozen miles on it, all local streets. I'm guessing it's more likely I effed it up than a bad sensor. F me. We're driving to Texas in 2 weeks to bring back a camper trailer.

 

Overfilled by a bit isn't gona hurt anything, even slightly underfilled isn't gona cause damage right away.

The correct check temp is 97-115F, trans in park and engine running.

 

That can't be right, at that temp you'd be on borrowed time and the trans would feel like it was slipping with a bit of flare under WOT or even on part throttle upshifts. I mean at that temp you could spray water on the trans pan and watch it boil off to validate.

 

I'm really hoping the Maestro readings are wrong. I've been researching and found that sometimes they are wrong as a result of faulty wiring or other issues. In the short time I've driven it, it didn't behave abnormally (slipping gears or other issues). I do have a scan tool, so when I check the temp tomorrow morning I'll connect that as well. I haven't used it for trans temp before, but I'm sure I can find that function in its byzantine layout.

Thanks for all the replies- it has helped settle my nerves a bit.

 

Curious about how the Maestro is converting temps? There are custom parameters that need to be entered to convert CAN bus info into readable temperature. Can't remember if they are needed for tranny sump and the torque converter, or just the TC... Do like Dm93 suggested, or if you have an IR gun, shoot the bottom of the pan. It will be accurate to within a few degrees. If the 246F temp is correct, that fluid is all but toast and needs to be changed. Assuming you can read TC temps on your system, I'd definitely use that for your reference. It is a leading indicator for the trans sump temp and can easily be 40F higher than the sump when you start lugging the engine. Driving in 4th gear is your friend when loaded or lugging. Good luck.

 

Oh Happy Days! Thanks @Dm93 - went out this morning and the outside temp was 64 (the low was 54), fired up the truck and checked the Maestro gauges. They read trans temp as 145f. Insert big sigh of relief here!

Thank god there's either a wiring issue or a bad sensor, rather than a transmission fubar. I couldn't find my scanning tool at the time (house is chaos as we get all the things together for the trip), but found it a short while ago. I'll repeat the test tomorrow morning and see what the scan tool says. If it shows close to ambient, then I know Maestro is the issue.

I'll watch the scanning readout and the Maestro, see what they say once it's warmed up, and know whatever Maestro shows (i.e. 240f) is actually the normal temp. That will have to do until we get back and can figure out the issue.

Thanks everyone for suggestions and comments.

 

I've seen that mentioned many times - drive in 4th when towing - and will definitely do so.

 

I'd bet it's a calculation/programming issue with your head unit rather than an issue with the truck as @MR5X5 says, you would have an A/T Temp warning light on if the truck was seeing that high of temp.

 

I'll reset the PIDs and see if that does it. If not, reach out to Maestro and see what they say.

I'm kind of disappointed in what gauges they have/don't have. Intake temp, load, etc don't really care. I'd like to see oil temp and pressure and coolant temp. The fuel% is blank becuase, apparently, Toyota doesn't have that data in the CAN bus.

 

Coolant temp should be there but there are no oil pressure or temp sensors and the fuel level sensor isn't tied to the ECM so fuel level isn't reported either.

 

To me the below are normal operating temps: Your temps seem kind of high.
My operating engine coolant between 185-2005 F*
Look at the screen print for Torque Con and Pan temp, About 160F driving 65 MPH freeway flat.
Thermostat PINNED open

Good advice to let it sit overnight and take temps again as a BASELINE.

I don't know about Maestro. I use Torque Pro app on my tablet with a Tanglog ODB 2 car code reader

At 106F* on the freeway the temps were about 8F higher in the Pan and the Con.
Live in SE Arizona desert - heat out the waazoo - 110F yesterday

See posts at https://www.tacomaworld.com/threads/3rd-gen-transmission-cooler-upgrade.482280/page-23.
My post is at #451

 

So resetting the PIDs didn't fix it, however the coolant temp now shows up. But it's also wrong - at startup in the morning, after a night with a low of 60f, the coolant reads 90f st startup.

I called the installer, who then called Maestro. This is paraphrasing what the installer said that Meister said; basically the gauges are not their focus and are something of an afterthought, while their first priority are the OEM controls like climate control, radio, seats, etc. They don't put much development into the gauges and have no intention to do so anytime soon. So I have nearly useful gauges. Wish I knew that before - I wouldn't have bought it.

 

What is the scanner you use? I don't see anything named Tanglog ODB 2 car code reader

 

Sorry about that.
Its a Panlong Mini OBDII Car diagnostic scanner. I use it with the Torque Pro App.
It plugs directly into the Electronic port under the dash.
It Bluetooth connects directly to the Bluetooth on my Samsung tablet.
I set the tablet up in the cup holder in front of the shifter.
Just look at those dials/gauges !!

Torque pro app costs what - $10.00 bucks. This scanner costs say $23.00.
You get all this scanner info and temps for under $40.00. Its on your tablet and is not anywhere near permanent - just turn off the tab and unplug the scanner. Works for me and my truck is a 2021 TRD Sport DCSB Automatic.


I use Torque Pro and got the PIDS off this Tacoma World site.
I developed confidence in these two items after checking the Transmission Oil temp in the car's temp check mode.
If I remember correctly the car in Trans Oil check mode is between 95 and 115F. The above #14 read like 96 and 115F
I had it connected up for the trip between Tucson and the Grand Canyon - say 350 miles. No Problems in 2-3 years.
Its a fault code scanner and you can also use it to check your engine operation.
Works on my 2009 Honda Accord

 

I use the Torque Pro app with the below scanner with the attached PIDS.
Tacoma 2021 DCLB v6 automatic trans, pinned external cooler.


OBD2 Mode and PID: 221627
Long Name: Transmission Fluid Pan Temperature
Short Name: TF1 (pan)
Minimum Value: -40
Maximum Value: 350
Scale Factor: x1 (do not change)
Unit Type: F
Equation: (A*459/255)+(B*1.6/255)-40
OBD Header: 701
Diagnostic start command: (leave blank)
Diagnostic stop command: (leave blank) automatic trans
Overrides PID: Does not override any PID

OBD2 Mode and PID: 221628
Long Name: Transmission Fluid Post-Converter Temperature
Short Name: TF2 (conv)
Minimum Value: -40
Maximum Value: 350
Scale Factor: x1 (do not change)
Unit Type: F
Equation: (A*459/255)+(B*1.6/255)-40
OBD Header: 701
Diagnostic start command: (leave blank)
Diagnostic stop command: (leave blank)
Overrides PID: Does not override any PID

Some results with pinned external cooler. Notice the TF1 and 2 results and the Ambient Outside Temp, speed and mileage of the trip. Truck was packed for camping say, 600 lbs including me on mainly flat freeway driving.

 

Hard to believe they don't have a page that allows you to adjust scalars..? You sure such a page does not exist?

 

That is awesome! I really wanted something that would display on my head unit screen, but that doesn't seem possible. I have IOS and could use my iPad or iPhone, just need to figure a mounting solution. The Kenwood HU is huge and takes a lot of space.

It looks like it's not plug and play, and that you had to do some programming? Is that dependent on the app you use? There isn't an IOS Torque Pro app, but they do have a long list of compatible IOS ones - For iPhone: Car Scanner ELM OBD2, OBD Auto Doctor car scanner, Carista OBD2, OBD Fusion, EOBD Facile, DashCommand, inCarDoc, OBDLink, Dr. Prius, etc.

I'll dig through those and see if any of them would work. Clock is ticking... I have 4 days and I have a mountain of to-do's, including wiring a 30amp circuit for the camper (and I'm working M/Tu). Hopefully I can find one that isn't onerous to install and configure.

Thanks for the info!

Edit to add - I used ChatGPT to find out if any of those apps have CarPlay compatibility so I could use it on my HU. Turns out, CarPlay won't allow real-time displays... fuckers. So, no app will allow me to see current status. I guess it updates when the car is stationary? Not sure how that works...