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Hi, in case anyone hadn't seen my introduction, I joined here because I was just poking around the internet looking to see if there was any interesting feedback regarding products with which I have had engineering involvement.

I was involved as an engineer with the 4G convertible top. I may be able to answer some questions, but I'll point out that this was (at this point) activity that is about 5 years in the past and I have changed employers since then, so there is the possibility I might have mistaken recollections, but for anyone with an interest I'm sure I can piece together any gaps.

My responsibilities didn't include vehicle level responsibilities. I understand, as far as that goes, that when you push the raise or lower button that lowering the top starts with the vehicle lowering the windows. That knowledge was peripheral to my area of responsibility, and anything more in-depth might be something I can't help with - for example, I'm not familiar with trouble codes or the meaning of the beeps. I had some knowledge about that, but I've forgotten it.

As for the convertible top itself, I will be able to describe it in detail - my hope is that by describing the system, perhaps the information will be helpful for those needing to resolve issues. I've seen that the most frequent convertible related subject matter seems to be that the convertible top won't close. By understanding how the system works, perhaps I can help in resolving this kind of issue.

In participating in these forums, I'll also point out that I know things about design history and testing issues, these are probably things I'd be bound to not share. The information I will offer will be things that could probably be figured out by anyone with access to parts and a little time to study them.


The Mitsubishi 4th gen Eclipse convertible is a cloth convertible top with a back window bonded to the fabric. The top raises and lowers by way of a hydraulic rotary actuator with 2 hydraulic cylinders for raising and lowering the 5th top bow and 1 hydraulic cylinder for raising and lowering the tonneau cover. The hydraulic system is operated by a single pump run by an electric motor, and with valving which is triggered by electronics which receives signals from certain switches I'll describe later. When the top is closed, it is secured at the 1st top bow to the windshield header by two manually operated mechanical latches.

The convertible top has 5 bows and siderails are in 3 sections. Starting from the rear, the 4 & 5 bows operate from a common pivot at the rear of the rear rail and the 3 bow operates from a fixed (non-pivoting) attachment at the front of the rear rail. The 2-bow has a pivot attachment to the front rail and is constrained somewhat by a cable. The 2nd through 5th bows are all made from aluminum extrusions. The 1st bow bolts to the front of the front rails and is a large aluminum casting (all of the side rails are aluminum castings)

A stamped metal link connects the center rail to a bracket on the hydraulic actuator, setting the mechanical motion of the center rail during top operation. A 3-piece linkage connects the rear rail to the center and front rails to control articulation of the front rail during top operation. The rear rail is driven through a link bolted to it which is operated by a hydraulic motor.


Before operation, the latches at the 1-bow to the windshield header should be open. The 1-bow should raise slightly, and switches in the receivers on the windshield header will detect that the pins on the 1-bow have raised. (There may only be 1 receiver that has a switch, I forget)

1) When the user pushes the open button, first the vehicle body control module lowers the windows.
2) When the windows are lowered, the vehicle sends the signal to the top to begin opening.
3) The hydraulic cylinders are extended to raise the 5-bow. These hydraulic cylinders have switches to signal when they are extended.
4) When the signal is received that the 5-bow is raised, the hydraulic cylinder to open the tonneau cover begins to extend. The flipper doors raise with the tonneau and remain in the down position.
5) When the tonneau hydraulic cylinder's position switches indicate the tonneau is raised, the convertible top will begin to cycle until a position switch on the side of one hydraulic rotary actuator detects that the top is lowered. As the top lowers, a mechanical cable connected to the rear rail drive link will allow the flipper door to raise.
6) This will trigger the hydraulic system to close the tonneau cover. When the tonneau cover is in the closed position, the latch will close.

I don't recall the latch details, I think it was also operated by a hydraulic cylinder, but that was a little peripheral. My company supplied the hydraulic system with the top, and that included all hydraulic cylinders, and we supplied the flipper doors, but we didn't supply the tonneau cover. I think we supplied the tonneau latch, but it wasn't my area of responsibility so my recollection about that component is a little sketchy.


Pretty much the reverse of the above opening procedure.


Generally speaking, the easy part is raising and lowering the top. It is the 5-bow and tonneau cover hydraulic cylinders that need the release valve opened. The hydraulic pressure for these cylinders does not require pump pressure to hold position (if there are no system leaks) and the cylinders will not move unless you open the manual operation valve.

My recollection is a little hazy, I remember something about a hex-shaped emergency tool and you use this to operate the tonneau latch and the 5-bow... What I do remember is that operating the 5-bow by pushing on the 5-bow was a good way to bend linkages, resulting in the 5-bow not properly sealing when the top is closed and potentially interfering with the top being able to lower completely when the top is open.


Some things you can check for, armed with the knowledge of how the top works, might make it possible to do a simple repair without having to go to a dealership. Here are things which might cause the top to not operate:

1) A hydraulic leak or the manual operation valve may cause the top to raise partially or raise slowly. Either way, the pump will operate for some time and when the expected switch isn't activated when the computer expects to see it, a fault code will be set.
2) Another thing that could happen is that once the tonneau or 5-bow is raised, a loss of hydraulic pressure might cause either or both to start dropping back down. I think this might be detected when a switch changes state, which can either interrupt operation or cause the system to change cycles. If this is happening, watch out for parts crashing into each other.

3) If the system reaches a certain point, and it keeps pumping (like say for example the 5-bow raises but the top doesn't start lowering) it might indicate that a position sensor/switch is not working. Check for broken wires or in the case of the top up/down switch on the side of the hydraulic motor, maybe the bracket is bent and the switch isn't contacting properly. You might be able to fix broken wires or bent brackets on your own. Otherwise it might be a bad switch which would require a replacement part.
4) Receiver switches sticking in the 1-bow (or forgetting to unlatch) can keep the system from cycling.
5) If the windows don't lower it can keep the system from cycling
6) The trunk being open will stop the tonneau from opening (IIRC)


Maybe I'll leave it at that for now, if there's any questions I can answer or corrections I should make I'd be glad to hear it!

I have a 09 eclipse convertible. The tonneaue goes up the top goes down but the tonneau will not go back down to finish the top down process.
Any thoughts as to what might be wrong?
Thanks a bunch!

14 Posts
No I haven't so frustrated
I finally.did. the pressure release valve had been and not tightened correctly so hydro fluid was leaking out of the pump. It cause air in the lines and the whole system to.sieze up. I got everything tightened correctly refilled fluid and it was hell to get the air out of the lines and fluid thru but now everything is working as it should. I hope this helps
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