993turbo

The cruise control on my 84' S2 is not working.

I've measured that the cruise ECU gets 12v, and it does.

Where do I start looking for faults?

Cheers!

Lizard928

The troubleshooting for the CC unit is actually very good.

But I would recommend removing the cc brain and rerunning every solder joint in it as they are common for bad solder joints causing them not to work.

Ducman82

follow the steps in the WSM.... super easy, and helps pin point the problem quickly.

Orantes

Re-soldering the cruise brain worked for me. It's been about 8 years since and the unit is still good.

993turbo

I will take a look at the solderpoints in the ECU.

993turbo

Been doing the WSM troubleshooting. All works, so its the CCU.... Ive tried to resolder it, bu no success! :-(

Ducman82

Have you tried the oven trick?

993turbo

No? Please do tell??

Ducman82

take the unit out of the case, cover the component side with foil, and stick the solder side up , (on a pan) at 350 for 10 ish min in an over. it will heat up the joints and re flow them. worked for me and a few others.

993turbo

Will give it a try :-)

350*F = around 175*C

Will do it right away. Cheers!

993turbo

''Dinner'' is almost ready!

Crap iphone picture:

h011yw00d

I'm not sure if 350 will do it. I think the reflow temp is around 365 or so IIRC. I did mine at 385 for 8 minutes and that did the trick. Did it a year ago and the CC still works like a charm.

993turbo

Yes, 350 is a bit low. Did not melt the solderpoints. I did 380 for like 10 mins, but it did not do the trick. :-( Still not working. Need to source a known working CC unit....

siscogts

Amazing.I see pictures of guys with a complete snap-on cabinet, full ofevery kind of car tools..... and they cook the cc brain in his kitchen oven.and a lot of people is wasting also time to search for the right oven temperature.....
I visited a lot of Bosch car centers, Porsche specialist garages, mechanics....and never see a bosch home oven...anyone guess why?

I keep on saying that the oven is a bad bad idea.
reflowing is farway better, if you know which component stands the heat of the solder and which doesnt'.
Electrolithic condensers age and(if you're unlucky) perish.....they can stand heat, but the oven is not the solution for this kind of components.They need to be changed for some cents each.that's it.

my 2 cents
Francesco

DZGunner

I literally just put my CC in the oven today and tested it, its working now. Although i definitely did deform some of the plastic of some of the components. I was pretty sure i ****ed it up and was about to buy a used one. before i did that i tested it though and it worked. My god it worked.