Its a safety feature actually. Engine braking slowing the car on slopes. I'll just control the rev to overcome it.
Don't need Proton service center's help.

bypass with what? so it can behave like plain campro? don't..
u can disable the auto downshift by jumping some pins on the ecu iinm.. i've seen the diagram, but forgot what pins & where to look for that diagram again..
downside of this mod is it also disable auto upshift

u got some solutions here:
1 : Change to MT, no auto downshift.
2 : Please set rempit mode to on during downhill/slope.
3 :

apa cock yang dimaksudkan?

azyune
Yes.
Cock on fuel line? It a choke which is not necessary as once the engine shut down, fuel pump also stop and the process between fuel pump to injector
is straightforward. No worry about extra fuel along the line.

saru04
IAFM is there for a reason. Bypass it will render the car sluggish at low end torque. Unless you mod the intake and top to CPS...lol.

cloudstrife07
Mine also auto downshift but will upshift even with slight input on the throttle. So, I never bother.

hi, the original mitsu auto trans comes with invecs ii system which is adaptive program@sometimes known as fuzzy logic. Well, its mitsu tech, so no need to brag about that too much for prtn. Since persona, the tcu has been altered due to complaint on adaptive program including changing the lock up protocol coz 1st gen gen2 with campro, the 3rd n 4th gear keep hunting even with slightest throttle input. Original intent to make it feel more brisk in acceleration to mask the infamous torque dip but it seems to be annoying. Many things being change for the tcu since persona and newer prtn which using the same transmission. With iafm n cps, so, newer tcu program works well but herm, the weight of the car still be the biggest problems for prtn. Even for b segment, its weight nearly the same as c segment japs car during that time. The iafm even cps output is commendable during that time if compare to same emmision comply engine, the probs is the weight.

Now the weight problems is almost not a problem coz they already know how to shave unnecessary weight, and heard that they r now focusing on increase fuel efficiency in town driving which still not doing that great currently. Its good, but not great.

Ops sorry, nothing to do on updating ecu, just when it auto downshift n u feel that uncomfortable, just feed more throttle to trick the tcu that u r on a flat road by matching the engine speed with the wheel speed, it will cancel the auto downshift.