Knowing how an electronic component is supposed to work is very important when you are troubleshooting it for a problem. It can make the difference between replacing parts because you know they are bad and replacing them because you think they are bad. Half the battle in troubleshooting a device is knowing how it’s supposed to work, what to expect from it, what is normal and what is not.
In the world of transmission diagnostics, from time to time there is a scenario in which the diagnostics performed ends up being a waste of time. In some situations it can be partially attributed to the “out of sight, out of mind” syndrome, as is the case with a 4L30-E transmission in Isuzu Trooper and Rodeo vehicles. The problem occurs mostly after the transmission has been re-installed.
The past winter months brought to surface a condition of no upshift from first gear when cold with the SAAB/Volvo 50-42LE transmission. When it warms up, all shift sequences are restored. The time in which this occurs varies.