Solenoid testing

[Gumboil]

Good day guys

Im hoping you guys can assist me in testing some solenoids. First time ever for me, so not quite sure here to start. I did some Googling, but I cant seem to find where all this testing is done. Might have overlooked it :-(

Anyway, Im stuck in limp mode on my W210 with a 722.606 tranny and my iCarsoft scanner gives me a error code of P0748. The scanner says its "pressure control solenoid 'a' electrical". I know where the solenoid sits, but wanted to know how I go about testing it. Besides draining tranny fluid, removeing sump and all that. I got some diagrams, resistance values of individual solenoids and images from Google, suggesting various pinouts to check, but unsure of how to go about it all. Is all this done with ignition on or off? Will I be doing all tests by the 38pin connector etc.

I would greatly appreciate it if someone can give me a rundown of how this is suppose to be done.

 

[Flyinspanner]

Think they are on the electroplate in the trans. :- so even if you check resistances, it’s still drain and drop sump pan to access it and swap any duff bits or whole electroplate

 

[Gumboil]

I just want to understand this. So the TCU logs its own fault, then sends that same fault code to the ECU. So clearing the ECU fault codes wont clear the TCU fault codes. I have the iCarsoft MB v1 scanner, which cannot access the TCU with the non iCarsoft 16-38pin adapter cable I bought separately. So everytime I clear the ECU codes, that same P0748 code comes back again. So after every restart the TCU sends the ECU that same code. Im going to test the solenoids and whatever else I can, while I wait for another guy to bring his Star diagnostic machine along. Same guy I have been waiting a month for lol.

When I asked the tech support at iCarsoft if it would clear transmission faults, they said it would. That was obviously dependent on having the original iCarsoft 16-38pin adapter.