95 Park Avenue Cruise Control Problems

[flango]

My Buick cruise control is kind of spotty in that: I set the cruising speed and after a bit it seems to forget that it's set at 68 mph for instance and simply decelerates. It doesn't decelerate like it would if it were not on cruise and I simply let off the accelerator. It slowly starts slowing down. I touch the accelerator and it 'seems to remember' that it needs to be at 68 mph and it will accelerate to that speed. (sometimes overshoots and then backs off). The CRUISE CONTROL light never goes off so I don't think it's a brake switch problem. Sometimes, it just won't take when I press the button so I have to maintain speed myself until it decides that its going to work for me. Any ideas out there? Thanks

[JESSICAR]

Please let us know your fix when you find one.

I have a 95 PA, and the cruise just started doing the same. I set it, and then it slowly loses speed, but the Cruise light never goes out. Then last friday, there was nothing.. didn't even seem as though it engaged. My husband put a scan tool on it, and the lever was working ok (you could see it switch from on to off), and looked as thought there was voltage going to the servo.. but it just wasn't holding. Checked the brake lights and third light, all working. Huh.... So..We replaced the servo on Monday, junk yard parts, and the up to third one in didn't seem to make a difference... then I started messing with the lever switches pushing them on/off and jiggling the wire. Then it started working, so I thought the prob was fixed, like the computer needed to recognize we had a new part? Or was it because I was messing with the lever? Well, it worked great yesterday morning and after work, setting, holding, accelerating and coasting just fine... Now this morning...nothing. Grr!! So I started jiggling the wires again and the switches, and it came on.. but won't hold. But I can tell it was on because when I switch it off and just rest my foot lightly on the accelerator, I can feel it come up. But then I try it again, and nothing.. geez.. I wonder if it is the lever??

Would love to know what peoples fixes were. I don't want to put a ton of money into it, using jy parts if possible. But seems no one finished topics here..

Frustrating! lol

[Jrs3800]

Both of you need to check the vacuum lines to and from the Cruise Servo, it will be bolted to the top of the Trans below the Throttle Body...

[JESSICAR]

Ok.. we are getting vacuum.. and so we brought it to a mechanic.. he said Servo.

Just for shits and giggles, we also put a VSS (Vehicle Speed Sensor). Then we put a "re manufactured" Servo from a parts store in.....

Nothing. Not a damn thing.....

Actron scan tool showed us a trouble code of P1558 "Cruise Control Servo Indicates Low"...... Does anyone know what this means????? This is getting pretty frustrating!!!! We tried another "junk yard" servo, and it worked nicely for about 4 minutes, then FAILED!!!! Again, we got P1558 "Cruise Control Servo Indicates Low"----Not sure what to check next.... any advice, anyone out there have the same issue?????

Thanks!
-Jessica

[Jrs3800]

First, are there any other codes?

Also have you checked all of the vac lines to make sure that none of them are collapsing?

There is a possibility that the brake switch may be going bad, if there is too much resistance in the brake switch it can also set that code..

Not sure if thats your problem but its a direction to go in.. The Servo very rarely if ever fails

[JESSICAR]

Thank you for the quick response again! The vacuum lines are all fine and there are NO other codes being set.

We will take a look at that brake switch today. We have the consumer version of Alldata and did see where it is located. Hopefully it's just a matter of pulling it out and putting one back in. I saw this deal about adjusting and curious how one would even attempt that.

If there are any tricks to installing the switch please let me know. Hopefully that will solve the problem.. otherwise.. back to the mechanic it goes. But there couldn't be too many more avenues to travel on this one.

We really appreciate all your help... we had read a bit about people saying brake switches going bad, but never anything about too much resistance possibly setting a code. :P

[ZiggyPA]

I kind of have the same problem. Sometimes the CC works, sometimes it doesn't. When it does work it often disengages after a while. When it does this you can't activate it again for some time. The cruise light always works though. Noone has ever been able to find the problem....

[JESSICAR]

Well .. here is the deal.. ha ha

Before we were off to the parts store, we took the sound panel down under the steering wheel, and tried to locate the switch. My husband moved the switch (I guess turned it?) and had wiggled wires just to make sure he had the right area..

We went to the parts store, but no one carries the Brake/Cruise switch side, only the Brake/Tran side. Figures.. So we figured that we would just take it back to the mechanic.

We were driving around trying the cruise again (for shits and giggles).. and it was working.. everything was working. We drove miles without any issues, again testing everything, coast, resume, set, all of it was working perfectly. So we kept leaving a different intervals during the day and taking long drives testing it out, and it never failed.. not once.....

So now I'm curious.. (if it works again today), can that switch just been out of adjustment, and by turning it fix the problem? I thought I had only seen issues with the switch being out of adjustment that the cruise would surge, but not set a code then thusly becoming useless.

This is just bizarre! LOL.. I hope it's not a fluke, and it continues to work......

[Jrs3800]

Its possible that he might have broken up some corrosion on the pins in the connector dropping the resistance... I'd unplug it and plug it back in a few times and see if it continues to work...