Computer upgrade trouble

Is it the same tank of gas, or did you fill up since the upgrade?

I have odd drops in MPG occasionally. I drove to the oil change Saturday at 48MPG, and now I'm around 45MPG if I'm lucky. Don't know what's up, but I did add more of the X-1R lubricant in hopes it gets me back where I want to be...

 

If this behaviour doesn't go away with a fresh tank of gas you should go to a dealer. If I understand posts by mdacmeis in other threads, the computer is completely re-programmed when any update is done (that is, all of the programming is re-loaded). If so, then it is possible that some part of it got corrupted. Error-correction codes and self-tests are not perfect.

Again summarizing from other posts, it is crucial that the car have a charger supplying power to the 12V battery throughout the update (the 12V battery supplies power to the computer; during the update the engine will not start and so the car cannot recharge the 12V battery by itself), and that the update is allowed to complete without interruption. In other words diplomatically remind the service department that the Toyota procedure must be followed *exactly* with no shortcuts.

 

Could you explain why this upgrade was needed?

 

FWIW, I've been fanatical about tracking my mileage and the various driving and weather conditions. Since the update, my mileage has dropped about 5 mpg consistently (3rd tank since). Now, it may simply be that the weather is getting warmer and warmer and having the A/C on Auto (as I always have had it) is having that affect, but I thought I'd mention it.

 

I highly suspect tire inflation to be the problem here, especially with repeated reports of the mechanics filling all tires to 32PSI instead of 2PSI's extra in the front, as mentioned on the driver side door.

The first oil change I had, they deflated my tires from 42/40 to 32/32. Second one they didn't adjust them - unfortunately that was also when they rotate them, so it was then 40/42. Buy a $1 tire pressure gauge and check them, and at the very least up it to 38 front 36 rear.

-m.

 

well let me shoot down the air conditioning theory. i am averaging 54.2 mpg in 100º heat for three days that we had that kind of weather (crossing fingers)

one of you said you had your oil changed. have you checked to see if it was overfilled? that has been a problem for some here and overfilling will affect your mileage.

as for tire pressure, i use a highly accurate digital gauge and my car came from the dealer at 38.5/36.5. when i took my car in for its 30 day checkup, i checked the air pressure of the tires since they mentioned checking the pressure and the pressure was 38.2/36 so apparently 38/36 is the new standard.

i had my update too early to tell as it was done in the middle of my 2nd tank of gas. and as far as going into EV mode, my car never really did EV that much. people talk of taking off from a stoplight in EV mode, well ive tried it several times and i cant seem to do it. i even tried accelerating up to 25 mph, engaging the cruise control and trying to bump up to 40 mph and that didnt work either.

but to be honest with ya, im not that hung up on running in EV mode since the battery only has the charge to run the car for only a few miles at best anyway so i dont see the point to forcing EV mode unless you are just moving your car from one spot to another for washing or cleaning or something.

as it is, the ICE runs so intermittently at low speeds that its not a concern for me. when i first got the car, my freeway mileage was way better than my city driving but now things are starting to even out.

my freeway driving is averaging just over 2 mpg above EPA, i wish i could do that on city driving. that would be nice. but i will say my city driving has gone from about 48 to nearly 53 as far as i can tell ( i do mostly city but mix in several freeway stints) and its still rising.

i know its the wrong thread, but my mileage right now is

tank # 7 383 [email protected] mpg

overall MPG (last tank not included)computer 52.3 by fillup 51.9 over 2943.7 miles

 

I have not received from my dealer or from Toyota a notice about the need for a comouter upgrade. Until I do, I'm following the don't fix it if it ain't brokenlaw.

I have found that frequent use of the air conditioner reduces mpgs (50 to 48). Lower tire pressure has the same effect; I'm currently using 38/36.

 

Computer upgrade

I had the 40D work done last week. They also rotated the tires and followed my instructions about tire pressure. They were going to upgrade the Nav but they don't yet have the CD from California. I had 2nd oil change with synthetic 5-40 and what a shock this time. Charge was $8.53 per quart for the Castrol.

I'm now going to price the oil at other locations to see what the price really is. May buy somewhere else and take it with me for oil changes.

 

My tire pressure has been consistent, and set to 38/36 as others have. Although I do have an accurate digital pressure gauge, I've found it really handy to have the pressure calibrated stem caps. I ordered a set of 4 from garage-toys.com for about $12 and they're great. The end of each stem cap is color-coded based on measured pressure. They're green when properly inflated, then they change to yellow and eventually red as pressure is lost. Takes 2 seconds to glance at all 4 wheels every now and then to be sure they're still OK. I love no-brainers.

 

http://www.customwheelweights.com/tireminders.htm is the only place so far that lists 42psi at all, and not cheap.

I'd hate to plop down $20 plus shipping (2-42psi and 2-40psi) and find them gone some morning...

 

I'd check Truck Stop Shops to see what they have.

 

http://www.danielcurran.com/Insight/insight3.htm says the stems should be replaced yearly.

Does anyone know if the tire pressure monitoring kits that run over $200 last 10 years?...

 

i heard that those tire pressure stem caps were not very reliable. and i dont mind checking the tire pressure. i only do it once a week or so and i have yet to see any tire pressure change.

 

Well, for me they were less than $20 delivered, so it's not a big investment if they don't work out. When you order them from garage-toys.com, you have to specify what pressure you want them set to. They're supposed to maintain their accuracy to 2 psi. Since I wanted 38/36, going up to 40ish seemed plenty. I still have my handy digital pressure gauge, so I'll check it manually from time to time and let you know if there's a discrepancy.

 

within 2 PSI???

hmmm....

 

Was this problem ever resolved?

I just had my SSC-40D done a few weeks ago, and have been experiencing the exact same behavior! Very puzzling...