I still plan to take the car to the shop next week, but I've been testing things as I put the latch back together.

The epoxy I put on the un-lock pneumatic solenoid will hold just fine. It didn't come apart, it just cracked a couple of the retaining clips around the circumference.

UNLOCK MODE:

When I press the unlock button the electrically activated pneumatic valve clicks to route the pressure to the unlock solenoid, but it does not REMAIN engaged, and the pump does not engage to create pressure to activate the solenoid. If I apply a little pressure to the inlet and press the button, there is a little bit of movement in the solenoid when the electric valve engages, but because it disengages almost immediately, there is no unlocking action other than a little wiggle...

OBSERVATIONS:

Why does the electric solenoid disengage so quickly?
Why does the pump not engage and make a little pneumatic pressure?

PERHAPS THIS IS DUE TO A LOCKOUT CODE STORED IN THE PSE?


CLOSE ASSIST MODE:

When the latch is clicked to the first closed position, the pump engages, and there is some pressure felt at the pneumatic tube to the solenoid, but it is very weak compared to what is needed to activate closure. The pump runs for several seconds and stops, presumably with a timeout. In a couple of seconds the pump engages a second time for a couple of seconds with a different sound.

OBSERVATIONS:

Why is there not enough pressure generated from the running pump to activate the closure solenoid?

If I cover the tube from the pump with my finger and activate the closure cycle, the pump runs for the same amount of time. In theory, I'm thinking if it sensed the pressure had reached the specifications, the pump would have disengaged earlier...

In the closure scenario, I'm thinking there is either a leak in a hose that prevents the pump from reaching full pressure, or something in the pump is not creating the pressure in the first place.

The connectors at the pump are labeled. The one to the trunk latch is labeled "HECK". If I disconnect it at the pump and apply a little pressure to the tube with my air gun, it will READILY operate the close assist.


SUMMARY:
I'm thinking the pump has a problem... It DOES engage to close the trunk. It will hiss if the tube is disconnected while the pump in engaged, but doesn't seem to create enough pressure to operate the closure.

The unlatch mode isn't really trying, and I am guessing the stored code is preventing it from engaging.

If anyone has experince with this, please chime in. I will share my observations with my shop next week and we will go from there...

__________________
02 S500
92 500SL
92 400E (Sold)
87 300E (Sold)
83 300D Turbo (Sold)
75 300D (Sold)
74 240D (Sold after 20 years)