SilentSpring

Hey everyone,

So I have an interesting issue with the cruise control that I was wondering if anyone had any ideas about.

Sometimes it works and sometimes it doesn't....if it's below 45F it usually works all the time, if it's above that, it's touch and go.

However last night I noticed that while in 6th the car was jerky(by jerky I mean felt like the throttle was opening and closing slightly causing a decel and then a surge but speed would not change) and the cruise would not engage....pressing the set button caused the green light to come on for a split second and then go off.

I shifted to 5th and the cruise engaged no problem, same speed, shifted back to 6th and cruise wouldn't work. None of the jerkiness either while in 5th.

So I tried 2-4 and cruise worked for all of them.

Any ideas or suggestions??

Thanks in advanced!

EDIT:

So I figured out some things after being able to play around with the car a bit more...it depends on the position of the shifter while in 6th gear only. If the shifter is moved to the end of it's 6th gear stroke the jerking starts and the cruise will disengage, however if the shifter is pushed up ever so slightly then the cruise will engage and the jerking stops....

That also explains the temperature problem and once it sits....the metal is getting some heat into it and the parts are moving more freely...and the clearances are greater...

Now my question is this....what sensor's are involved with shifting gears? Neutral safety...but what else? Is our ECU aware of what gear it's in, and if so how?

There are no cel's for this and nothing stored....I don't have a way to data record to see what's going on.

Thanks all

SilentSpring

Bumpity ....any ideas?

alnielsen

iTrader: (4)

Have you looked for ECU error codes?

SilentSpring

Yessir....none

SilentSpring

B-bump...anyone?

Does someone have a flowchart for troubleshooting cruise not working? I mean I'll just start tearing into the thing but I'd like to have an idea of where I'm headed.

SilentSpring

Bump....edited OP

SubliminalPollution

Not sure if this will help since I have no idea how it was done exactly.

I had the check engine light come on my car and I took it into the dealership to see what was wrong. The cruise control wasn't working either. The light came on because of the cruise control not working. The dealership cleaned the connectors or something and reset the check engine light. My cuise control worked perfectly after and it has been since.

SilentSpring

Hey Subliminal....

I'm planning on checking connections this weekend but there is no cel for this....only have one because my CAT auto-gutted itself (interesting feature that)...

This seems to be a sensor doing it....I don't have a manual for the 8 and like to have a good idea of where I'm pointed before I start dismantling things....even better to have values for those sensors =)

SubliminalPollution

Yea definitely being pointed in the right directions is critical. Unfortunately I didn't do this myself.