Cruise Control Problem - Toyota Tundra Forums : Tundra Solutions Forum

mbd0722 · #1 (**permalink**) 07-28-2006, 01:15 PM

Problem: Cruise Control lets the set speed drop 4 to 5 RPM after coasting on downhill roadway before set speed automatically reactivates (to much lag time after coast). This causes downshifting and higher excessive RPM to regain set speed on level road. The problem occurs between 35 to 70 MPH.

Example: I am cruising at the set speed of 55 MPH on level roadway, I am now going down hill and coasting downhill at 60 MPH, I reach level ground, I am still coasting, the speed drops to 53 MPH and the cruise control does not kick in yet, at 50 to 51 MPH the cruise control now kicks in and accelerates and downshifts the transmission with high RPM to bring the speed backup up to the set speed of 55 MPH.

I realize that down shifting to a lower gear is normal on climbing hills to hold set speed. The problem occurs at set speeds between 35 to 70 MPH causing what seems to me as very high RPM at 60 to 70 MPH. This occurs
using rear wheel drive. The Tacoma is a 2005 Double Cab 4X4 automatic.

Questions: Is there a setting in the vehicle's computer to set the + or - drift range for set speed MPH for cruise control? Do you think that the truck could have a problem with the computer software, or speed sensor?

Comment: I have never experienced this problem on other vehicles. The cruise control always held the set speed with normal downshifting and normal higher RPM on uphill, coast on downhill, and automatic set speed
reactivation on transition to level roadway without lag time or drift in the set speed range.

Is there a Toyota service technician out there with any insight to this problem? Thank You

TacomaOffRoadGrl · #2 (**permalink**) 07-29-2006, 10:16 PM

My cruise performs the same way. I believe it is normal...at least for this truck.

demoncleaner · #3 (**permalink**) 07-31-2006, 04:40 PM

I've read about this on toyota nation too. No help from Toyota dealers, and no TSB that I've seen. Just hope the 'kickdown' doesn't happen to you on a slippery surface sending the truck out of control... That auto tranny is too smart for its own good, best you trade in for a manual, where the cruise can't play tricks on you.