Lizard944

Just wondering if anyone has yet claimed the Nobel Prize for Electrical Engineering, by identifying which 10cent component in the CC brain fails, causing WOT response when CC is engaged? I did some searching and saw that someone replaced a blue capacitor with limited success, but the thread seemed to fizzle, and didn't sound like a "Eureka!!" discovery. I think the process that would have to be done would involve: 1.) Being single, and having way too much time on your hands. 2.) Find a good working brain and a bad one with the WOT problem. 3.) Do the complete resolder thing on the bad one and prove that a faulty solder joint is NOT the problem and that it lies somewhere in a capacitor, diode, chip, etc. 4.) Painstakingly swap out each of the components one-by-one from the good unit to the bad and road-test after each replacement, until you get it to work. 5.) Reinstall the suspicious part back into the bad unit to confirm that it's the culprit. 6.) Report results back here and have the 944/951 community build Shrines, Temples, and Pyramyds in your honor. Any takers?

75ohm

Have the thing cracked open yet? If so, post pix...

FRporscheman

Here's my contribution: After every swap of a capacitor (or whatever), you don't need to take your car for a test drive. Just leave it on jackstands and put it in gear. Beware a WOT'ing CC will proly blo yer enginez.

Mike C.

I changed the electrolytic capacitors, re-soldered everything, checked connections, etc.... I finally discovered a ground that went to the speedo cluster (I'm talking about an early car). Cleaning up this ground fixed it for real. I think I posted a thread and mentioned it way back when... Wish I had checked grounds sooner...

951Tom

Resolder all the connections on the computer board. Take apart the electric motor and clean the carbon tracks and resolder the wires. Worked for me, it's been trouble free for years now.

Ben951S

I thought there was a TSB about this, actually, something that makes CC 'unsafe' by applying throttle. Look up the TSB and see if Porsche fixes it (recall!)

=)

Rip It

My cruise control had 3 problems. (1) when set would go to wot (2) would set and later go to wot (3) would not work at all if I used the brake to disable it, would have to turn ignition off/on to reactivate it.
The solder joints on my cc brain were floating in flux (not good). I used a soldering station and removed all the old solder and resoldered it. That process took at least 12 hrs. It resulted in my cc not going to wot, hitting brake disabled it but didn't completely turn it off. It didn't set at the speed I selected either usually somewhere within 10 mph. The servo unit had severe grooves worn on the two carbon strips after 120km. Cleaning and moving the wiper contacts didn't help mine. I replaced it with a unit from a low mileage soon to be race car. It now works as it should, the only problem I am having is where to comfortabley rest my right foot.
I seriously doubt its a case of component failure unless its physically burnt.

User 41221

Joe Jackson on the Rennlist email list has been repairing these for years. You should try tracking him down and asking him, he's got the answers already. I have three cruise control brians that he has repaired for me. I have yet to have one of his repaired units fail on me.

Regards,

schwank

Easy.

Potomac-Greg

With a 944 n/a, how exactly do you know when it goes to WOT? I assume you watch the gas gauge. ;-)

PS: My cruise control does not hold a steady speed (fluctuates several MPH). Is it worth fixing? I'm inclined to just remove it.

Lizard944

[QUOTE=Potomac-Greg;5560645]With a 944 n/a, how exactly do you know when it goes to WOT? I assume you watch the gas gauge. ;-) "

Tee Hee ! Oh, I just saw your avatar. Appears to be a N/A on that track?
Ok, I'm laughing with you ; )
Actually, I just bought another brain from a lister who was parting out, and so far it's working great. I did the resolder thing before and it worked for about one week. Some people had luck with this being a permanent fix. They probably did have a bad solder connection. I looked at the board under a high-power ophthalmic microscope, before resolder, and didn't see anything suspicious. I think the heat from resoldering just stimulated a dried up eletrolytic capacitor enough to be temporarily within specs, then failed again. A common theme seems to be that when the CC starts acting up, it will frequently work when the car interior is hot. This seems to be such a common problem that I'm puzzled as to why some electrical guru hasn't been able to identify a single component as the culprit, or Porsche hasn't issued a TSB identifying the likely source. CC is a must for me as I seem to get "turf toe" easily on long trips

p_tothe_g

Don't freak out and shut it off! Mine goes almost exactly 10 MPH higher than the mph when "set". As soon as I hit the stalk, rapid acceleration for 10 mph then it works flawless. so if I want 75, I set it at 65. You get the point.

Lizard944

Mine did the "10+MPH " several times before it finally went to WOT as the default. Pedal would go completely to the floor, and in 30 seconds I'd be passing kids on bicycles and old ladies driving to church like they were standing still.

Will Feather

I love this, mines just pedal to the metal too!

It works correctly at some times, and others not. It's just another luxury that we have, but live without.

kandyinmyvan

Wow, I never realized so many people have this same problem. Mine goes WOT also so I just don't use it. Not a big deal and I've never cared to invest the time and/or cash into fixing it.