Pressure only is there if the pump has run, and after ten minutes of inactivity (or when the cycle is complete), the pressure is bled off. That is, in a system that is working OK.

NOW, if you are putting the top up and down manually and NOT ever pressing the button, there should never be pressure to stop you from moving things around. Pressure can only build if the pump runs.

Just to see what we can learn, try this: If it's an 05, yank fuses 5 and 6 from the underhood fuse box and try again, if the pressure never builds up with those fuses out, then the TCM is acting up. If the pressure still builds up with those fuses out, you have some sort of issue with the solenoids in the hydraulic module.

There are always TWO fuses for the top controls. If your car is other than an 05, we need to figure out what the fuse locations are, as they moved them a bit over the years. OR, just disconnect the battery cable and try it. If it builds pressure with the battery cable disconnected, it is NOT a TCM issue, it's a valve/solenoid problem.

But again, pressure does not build up without the pump running. If you can get pressure enough that you can't move things, then one of the solenoids is not opening properly. See, when the cycle is complete, all solenoids open and let fluid flow back to the tank. You CANT build pressure without the pump running, UNLESS you have a sticky solenoid that is preventing free flow of fluid as you manipulate the top manually. (The cylinders never loose all their fluid, they have fluid in them at all times. With the solenoids all relaxed, you can move the top on your own and small amounts of fluid will slosh around between cylinders and tank. If a solenoid is not releasing like it should, it will restrict flow and your movement.) The service manual actually describes all of this rather well.

 

Thanks pizza - so removing fuses 5/6 didn’t work, but disconnecting the battery did result in my manually being able to raise:lower the top without resistance or needing to do the hydraulic reset procedure. It did, however, also result in my windows no longer going down when the center top d lock is turned. Does this suggest both a tcm and a solenoid issue?

 

Ok, now that is weird. That would imply a bad switch in the frame or a TCM issue. Very odd that it was OK and now won't respond when you turn the crank.
You might make sure the fuses to the TCM are ok. (It was 5 and 6 in 2005, other years it might vary - the card in the fuse box should tell you what fuses are top-related).

 

Thanks mate. i'll reseat the 5/6 fuses to ensure i didn't improperly return them after i took them out.

 

SOME DAY, I am going to write a DIY guide on how the system works and some tips in troubleshooting.

SOMEday.........

 

Please do, I would buy one.