Does anyone know if you can set the ECO to be ON by default? If you turn on the ECO mode and accidently move the heat to high or the AC to LOW, the ECO mode turns off. It would be much better if you move the AC to LOW and then it returns back to the ECO mode by default when you move the temp back up.

I have had a number of occasions sitting at a traffic light wondering why the gas engine was running only to find the ECO mode was turned off.

Thank you for any assistance!

Bill

 

Bill,

The A/C compressor, and power steering pump, are electric, not an ICE belt driven accessories in the TCH. My ICE shuts off when I pull up to a traffic light but the A/C keeps going just fine...

According to my Shop Manual the ECO function is not a customizable option in the A/C system...

My pet peeve with the ECO is the way the switch was mounted out of the way... When I first tried to use it I opened the gas hatch by mistake... Personally, I haven't noticed any difference gas in mileage when using the ECO mode ...

 

Thank you for your comment. I understand the AC is not belt driven. Unless your battery is nearly full the gas engine will run at a traffic light with the ECO mode off. If you reach down and switch the ECO mode ON the ICE will switch off.

You may want to give this a try.

I totally understand about the Gas door issue! Been there, done that!

 

My understanding is this:

When ECO is on, the AC compressor will cycle on and off to average the temperature you've set. Cabin temps will vary slighltly, and in the two years I've had the car, it's not very noticable.

When ECO is off, the AC comprssor will always be on and mix heat to the temperature set point. This is why ECO turns off when you turn on the defog since the AC needs to be on for optimal clearing of condensation.

My beef is the ECO switch location (that is the DUMBEST place for an hvac button) in combination that ECO doesn't return after defrost. Argh.

I have noticed a small decrease in highway MPG when ECO is off.

 

There is no way to keep it on by default, unless they (Toyota) come up with a "better" version of the software and gives it away.

If I have ECO off, I can tell right away because the ICE will run much more frequently.

 

Does anyone have a clue as to what the ECO button really does???

I can't tell much difference between ECO "ON" and ECO "OFF"..... Although it seems that the AC isn't as powerful in near 100F and a sunny day with it off. RECIRC 'ON' covers that problem pretty well.

 

Best to read your manual - clear explanation there.

As I recall, w/o looking at manual, in ECO mode A/C will not cool below a specific (I believe76 degrees F) interior temperature - that's its only function. I.E. will shut off compressor when interior air temp cooled to 76 degrees - turn it on again when interior air temp rises above that.

 

Thanks Islander.... I'll go and check the handbook. Your answer would appear to be on the mark. In ECO mode, the car just doesn't cool and stay cool in the hot Texas sun. And, the system goes to RECIRC (or you have to put RECIRC "ON") and then the fan speed eventually ramps up.

Driving home from dinner-out yesterday we turned ECO off. Within in a few minutes the cabin got cold within minutes and we were able to move the temp from 70 to 72. Blower speeds went down and half way home I took it out of RECIRC. Nice and comfy and very little noise.

Wondering what in the heck we're saving here. With an all electric HVAC system, the only thing you're burning is electrons. Maybe you are supposed to 'suffer' while you safe gas to get an enhanced feeling about it???

 

ECO actually cycles the A/C on and off to approximate your temperature set point, so the temp will go up and down a tad. ECO off is the traditional mix where the A/C compressor is always on and the cold air is mixed with heated air to keep the cabin at a more consitsant temperature. This is why ECO turns off when you call on the defrost since the A/C needs to be on to expedite the clearing process and if ECO was on, there'd be a good chance the compressor would be off and you'd be left wondering why the windshield wasn't clearing.

As far as dropping a car from hot to cold, it shouldn't make a difference if ECO is on or off since ECO's function is for maintaining a set point.

One other point: we had a cross-country trip two summers ago and forgot to engage ECO one day. Our ususal mileage was above 40 MPG, but the day we finally figured out ECO was off, our milage was quite a bit lower, somewhere in the high 30's.

 

Interesting explanation. We had a '87 Camry that had the "eco" button on the AC that we just left on all the time and I had no idea what the difference was between the two settings.

I can put up with a little temp change in the cabin if it saves on fuel, but since the AC is electric powered how does it affect the MPG?