05 645 convertible, sometimes it won't crank

[rleidson]

Every once in awhile when I try to start it it will just not do anything. Sometime s you can wait 15 minutes and it will start, but last week wouldn't start for 4 or 5 days, then it just started. tried 2 days ago wouldn't do anything and just went out andit cranked today. HELP?

[jclausen]

I would consider replacing the Ivm module or integretated volatage control module' on the parts film they call it integrated supply module it's in group 61 on the film. It supply's voltage to the engine management system and when it goes bad it won't set a fault but it does do what you discriped when it starts to fail

[zulfib]

Alternatively you could do as I did. Open the ivm, find the pin that has cracked solder and reflow it. You may need a magnifying glass as it can look like a pencil mark.
It is usually the power pin to the main relay on the board. If you can't find it, reflow all the relay pins.

Mine has never missed a start for over 5 years since I fixed it.

[billpennock]

@zulfib I have everything open to the IVM but i can't get the plugs to release out of the top of the IVM. Is there a trick you used or just keep wiggling and pulling?

[billpennock]

@zulfib I have everything open to the IVM but i can't get the plugs to release out of the top of the IVM. Is there a trick you used or just keep wiggling and pulling?

Ok I finally figured everything out. For anyone running into this thread. I wish I had time to video the process but let me give a few tips. The plugs on the top each of some sort of latch. Start from the one closest to the firewall and sqeeze the outside and wiggle. The next one toward the front of the vehicle has a black swing arm with a push button holding it from swinging. Push the button and swing the bar away and it will come out nicely, same with the next one. The third is a squeeze on the outside (if I remember right as well) and the 5th is like the 1st. There are two brown wires that go over to a connector mounted on the side of the outer electronics box, that whole connector can be unlatched and pulled up to get some room without ever having to unplug either of the wires. Finally now you have to get to the bottom of the IVM. This requires undoing 3 screws holding the inner box in which the IVM and 2 other electronic boxes sit (I think they are the computers) . once you do that loosen all the wires out of the slots that hold them into the outer box and lift the inner box up and angle it so you can get to the bottom of the IVM. The plugs here are similar to the top. When those are out you can replace the IVM. When putting the plugs back on start from the plug closesest to the front of the car first moving back toward the firewall. After putting the bottom plugs on put the inner box back in. The 3 mounting screws holes are actually in the top of sockets into which the 3 base pins slide. Then put the connector back on the side of the box and close it all up. Cross your fingers and hope the car starts. It did for me. Of course that doesn't mean it was fixed since the problem was so intermittent but at least I didn't hurt it some more.

This is not that easy a job in spite of what others have said. I've done mechanical and electronic work all my life off and on but not professionally for over 30 years. That experience got me through but the people saying it's a 1/2 hour job are likely doing auto work all the time and currently. For them I'd agree. For the rest of us be ready to be a bit frustrated now and again.

Bill