sienna 2006 cruise control - reprogram?

poushag · #1 (**permalink**) 11-12-2007, 04:42 PM

We've had our 2006 Sienna XLE for about 15k miles. We really like almost everything about it - except the cruise control. The reason we hate it is that we live in a mountainous area and it doesn't hold speed the way our 2003 Honda Odyssey did. When going up a hill and the speed drops below the set point, the Sienna kicks down a gear and then almost immediately kicks down another gear. The result is that the speed overshoots the setpoint by a great deal and worse than that, the engine is gobbling up gas and revving up over 4500 rpm. In the same situation, the Ody would only kick down one gear and then gradually the speed would come up to the set point.

Has anybody out there successfully reprogrammed your cruise control? If so, how? I'm hoping this could be a DIY thing as I have a very high geek factor. But if DIY is impossible, then has anyone else had any luck to have this addressed under warranty?

Regards,
Andrew

splice57 · #2 (**permalink**) 11-14-2007, 08:53 PM

3 of the 4 Toyotas I have owned do the same thing. Our 2004 4Runner is the exception. I don't think they've mastered the cruise control deal yet. On my Tundra I just disengage at the bottom of heels and re-engage afterwards. It's a pain, but I hate the unnecessary downshifting.

mral1515 · #3 (**permalink**) 11-14-2007, 10:59 PM

Toyota does not have a reprogram for their cruise systems at this time.

wells service · #4 (**permalink**) 12-09-2007, 10:54 PM

the problem is not in the cruse control. the little 3.3 engine does not have enough torque with out shifting way down. the new2008 with 3.5 engine should be better. odyssey has always had a 3.5 with more horse power and torque, but with less gas mileage. the 08 seinna with the bigger engine still is rated at 26 highway which is 1 mpg better than honda. if you get the leather seat honda with cylinder shut off you could get 27-28 mpg.(but it will cost you about $2,500 more) you will probably never get the extra cost back in better mpg.

poushag · #5 (**permalink**) 05-02-2008, 08:42 AM

I have seen this hypothesis before posing that the Sienna engine does not have enough HP and/or Torque to make the cruise work well. I have to say that is is totally wrong. Here are the engine specs.
2003 Honda Odyssey: 240HP 3.5L VTEC
2006 Toyota Sienna: 230HP 3.3-liter dohc 24-valve V6 with VVT-i

The Sienna's 6% smaller displacement (compared to the Ody) is not significant. It does not account for this problem with the Sienna cruise control. And I can prove that by one simple fact. The fact is that I can operate the Sienna without the cruise in the manner that I want the cruise to work (only kicking down one gear to climb a hill). This means that the cruise control algorithm is at fault.

I know Toyota doesn't offer a reprogramming service for the Sienna cruise. Even if they did I probably wouldn't get it from them unless it was free (covered under warranty). I hope some 3rd party will come out with this instead. So if anyone hears about one, please post it here.

PS - And the gas mileage on these two vehicles that we owned is almost identical. When I divide miles driven by the amount of gas purchased the difference is statistically insignificant. We have been driving the same routes in the same area and buying gas at the same places.

MTeator · #6 (**permalink**) 08-10-2008, 10:01 PM

We have the same problem with our 3.3L 2006 sienna. It's not ideal, but we shift it manualy down to 4th at the bottom of the hill. Never found a hill it won't climb and keep speed in 4th gear. It's a shame it can't predict better.... I hate the drop all the way to 3rd, and then overshoot the speed (especially if you crest the hill while it has it floored.) It's a really bad cruise control algorithm. We really wish we had waited for the 07 3.5L.