My cruise control started cutting out on hills or under hard acceleration. The green cruise control light would stay lit, but the system would forget the set point and resume did not work. I could re-set the speed, and it would work again until the next time the car needed to accelerate to keep up with the road grade.
After searching this forum, I went to the junkyard and pulled a cruise control module from a base 2003 Matrix (behind the instrument panel- consult the madstyle manual- very easy to do- just gently pop the instrument panel trim off by pulling out and down, remove the top screw and pivot the instrument panel down and out, the cruise control module is a small metal box that is attached to a crossmember by a 10mm bolt).
I installed the junkyard cruise control module in my '04 AWD Vibe, and everything worked well. Until I met a hill. The car upshifted perfectly, crested the hill, and then the transmission would hang in 3rd gear too long, and then shift back and forth between overdrive and 3rd gear constantly as it was going down hill until I cancelled the cruise setting.
I let it do this several more times just in case the module or ECM was doing some learning (what do I know?)
I then started wondering if AWD Matrix/Vibes have a different cruise control module. This is what I found out. They do.
For anyone else with this problem, the correct GM part number for the 1st Gen AWD Vive cruise control module is 88969667. The correct Toyota part number is 88240-01030- the dealer website should say the following: Part Notes: Matrix; w/o XRS; w/AWD;w/o XRS, 4WD. The other cruise control module listed for Matrix/Corollas- 88240-02050, will not work properly for AWDs.
Usually, we find Toyota parts to be cheaper. Not the case here- a random sampling shows the cost to be $490 USD and above.
I found GM 88969667 on gmpartsgiant for $72.96. The odds of me finding an AWD Vibe/Matrix in the junkyard soon are pretty low, and I have a road trip to Colorado coming up, so the OEM part with a warranty is pretty enticing.
Hope this saves someone else some trouble.