Overheating at 88c?

So do you know the water pump is turning in text stream it'll tell you how many RPMs that water pump is turning most electric motors wind out at about 3,400 generally speaking I don't know what exactly the Toyota water pump will spin but I would think it would be similar and it probably can slow itself up and down as the car tells it to by looking at the connections on the pump it seems to have this capability so maybe your pump is not running at the higher speeds or something along those lines my gen 3 or my gym too I have never been able to get the engine hot enough to where I think it's an operating temperature and I'm in the southeast United States and 100° weather I run my gen too for 3 hours coming back from Charlotte in the middle of the day in the sun with or without the air conditioning if I whip over on the side of the road like to take a pee and whip the hood up on the car and ty can touch everything except the exhaust manifold I mean with my bare hand intake exhaust head all the hoses radiator top and bottom coolant inverter hoses all of them none of them are much over a hundred degrees it's like the car never warms up I do not know if in either car if the thermostats are bad but I do know that they warm up to a certain point and they cool off very quickly I go in the house 20 minutes and come out in that hundred and something degrees I was just feeling is down to 78 very fast and like I said I am not anywhere where it's cool

 

The overheating light can come on because of either of the two temperature sensors in the engine cooling system, or any of the several temperature sensors in the electronics and transaxle cooling system.

My guess is that the one reading you are looking at that is 88 ℃ just isn't the reading that is triggering the light.

 

That isn't what I thought; there are also half a dozen or so temperature sensors in the inverter and transaxle, and I thought you could also get the thermometer light from one of those.

But maybe I'm mistaken. I did find this table a while back in the repair manual, indicating the light comes on either because of the EHRS sensor in the hose tee, directly wired to the combination meter, or because of a CAN message from the ECM (which is where the sensor in the cylinder head connects).



The table doesn't exactly say under what conditions the ECM sends a CAN message to turn the light on. It could be only when the cylinder head temperature sensor goes over, or it could be because of that or a message to the ECM from the power management control ECU about inverter or transaxle temperatures. I don't know for sure.

The one in the cylinder head is the one that's wired to the ECM and is reported at the OBD-II standard PID for a coolant temperature from the ECM. The one in the hose tee is wired directly to the combination meter, so you will see that reading only on a scan tool that has the ECU address and PID for that.

More in this post.

 

That's the price of a bundle. What you need to use Techstream is (1) the software, (2) an activation key for the software, and (3) a compatible dongle to connect it to the car.

Toyota sells the activation keys at $65 for two days, or $1295 for a year. They have a particular $500 dongle that they test and endorse and will take your support calls about. The Techstream Lite bundle includes a full-year activation key and the official dongle.

Many people are using it with much less expensive dongles (there are known pretty good ones around $80 to $170, and many people are using cheaper ones around $30 or so).

With a cheap dongle and a two-day activation whenever you need it, you're already spending less time and money than you'd spend to even get the car to a dealer for them to do diagnosis on it.

Also, some people find that their cheap dongles also come with ways around the activation fee. Opinions can vary.

 

If you follow this post, you'll see I disconnected that hose tee sensor and substituted a variable resistor, and twisted the shaft to change the "temperature" reading. The tab in Techstream that is showing the temperature is the "Combination Meter Live" tab.

The "Engine and ECT live" tab is where you would see the cylinder head sensor temperature. That's the likelier one for a generic scan tool to be showing, because that's a standardized PID at a standardized ECU address. But if your app is showing the one from the combination meter, that'll be something interesting to know.