Hi christopher - I did not take my battery to the dealer. I had a friend jump me and then kept some jumper cables in my car for a week just to be sure it WAS only the door being ajar - and it certainly looks like that was it as nothing has happened since like that.

I did print the instructions on how to recharge the little battery with the big one, and put it in my glove box. But I havent been able to test it out as my battery has not been dead again....

The mileage question is a bit tricky as I had just had my transmission replaced and the 'brain' was working on readjusting to my driving patterns. Basically any time you disconnect the BIG battery the car needs to relearn. There are things your dealers computer can do to help it relearn faster but - it will relearn these by itself - just takes time and miles. So my mileage had dropped down to 19 when I had my trans replaced. Then I took it to another dealer who knew about retraining and he got the mileage back up to about 23. It is now around 25. I am still working on getting it better and better. ;-) I want to put the nitrous oxide (I think that was the gas) in the tires. I have heard from friends here at work that on any car you will get another 3 miles per gallon with that.

Hope this helps!

Kathleen

 

Kathleen, thanks for getting back to me! It does help a little. It sounds like the dealer probably reset your computer when you had the transmission work done. In the 06 highlander hybrid if the battery dies the dealer has to reprogram the idle speed according to TSB EG026-05 inorder for you to recover the same gas mileage (otherwise the engine comes on all the time, even below 40 mlies an hour). I was hoping to find a comparison since I'm getting around 17-18 mpg right now and I believe that my battery was disconnected before I got the car. I printed out the ISC Learning PRocedure just to keep it in my car for when I get the battery replaced. It looks like it only applies to the 06 model year. Dealers don't always even seem to be aware of the procedure which has been frustrating.

Cheers,
Christopher

 

Hi Christopher,

Thanks for pointing out the existence of TSB EG026-05. If you find that the engine runs too long when the HiHy is traveling at low speeds or at a standstill, then its reasonable to think this TSB applies to your vehicle.

After reading the TSB, it appears that you may be able to DIY without access to the Toyota diagnostic laptop. Make sure the engine is fully warmed up by driving on the freeway for an extended period - say 10 miles; or else by sitting in place and revving up the engine while the gear selector is in P, until the radiator fan comes on.

Then fully depress the brake pedal with your left foot to hold the vehicle stationary, and depress the accelerator pedal 60-70% while the gear selector is in D, for 30 seconds.

Then shift to P, make the car IG-OFF, and wait 5 seconds. Make the car READY again, check that the A/C is off, lightly depress the accelerator pedal and release when the engine starts. Then see if there's any improvement in the engine turning off when you are coasting at low speeds.

Hi Kathleen,

I'm interested to hear about why your transaxle was replaced, and at what odometer reading.

Regarding your tires, the alternative to using regular air is to use nitrogen gas. Don't expect improved mpg from such use, however.

If you can get nitrogen gas for free (i.e., at Costco if you buy tires from that source) then its reasonable to use that. If you have to pay, I'd suggest saving your money for some other purchase.

 

Hello Patrick,

I saw that, but I'm not sure if step three isn't required and since you can only set the computer to CALCLOAD with the toyota diagnostic computer I'm not 100% sure that it will reprogram the ISC. Either way I'm not taking any chances. On wednesday I'm taking my highlander in to make sure that it definitely completes the programming. I'll let everyone know if it improves the gas mileage into the 20's in city traffic. Which is where I do most of my driving.

Cheers,
Christopher

 

3. Select the following menu items:

DIAGNOSIS / ENHANCED OBD II / DATA LIST / USER DATA / CALCLOAD

The Toyota diagnostic tester kit tool is set to "read" Calcload (engine load in percent) in the above step 3. The vehicle's computer is not placed in any special mode via the diagnostic tester in this step. The tester reads out the actual load placed on the engine during the procedure to make sure a load of 40 % or more is achieved but it's use is not required. I have a Scan Gauge II and that can also be set to read out engine load in percent. You can probably use the dash KW meter to achieve 40+ % load.

 

Don,

Thanks for the clarification, this is my first computer based vehicle. I long for the simplicity of the 70's and 80's sometimes. I used to get 20 city 25 highway miles per gallon in my 1976 cutlass supreme which weighed about the same as the highlander since it used a lot more steel. If this procedure improves the gas mileage of my highlander I'll know I can perform it myself in the future. Since there is no guarantee that this is the reason my highlander is getting sub 20's gas mileage I want to see that COMPL that the toyota diagnostic computer is going to show to be sure. Could your scan guage II read that parameter?

Christopher

 

Just an update for any that may be interested. I took my 06 in to the dealer yesterday and they confirmed that the ISC Learning Procedure was incomplete in the computer. They reset it and at least printed out the page showing a complete in the column. I've only driven about 10 miles since then, but mileage calculated by the computer has continued to climb. It isn't over 20 yet (19.5), but I'm hopeful. I'll take it on a longer trip this weekend and see how it does.

Cheers,
Christopher