hello so my dads got a 2005 sequoia limited and awhile back the 4x4 function stopped working it now flashes “4 low” constantly even tho it’s been stuck in 2wd high for the duration of the problem. none of the bottoms do anything and we just replaced the 4x4 ECU (the green computer in the dash) and it made no difference. wondering if anyone else has ever had the same issue. have brought it to a reputable mechanic to no avail. would like to rule out everything else before replacing the shift actuator as it’s such a big job and the part is Very expensive!