Cruise Control Question

[macman90]

Awhile back my cruise control stopped working and at the time it wasn't a huge issue so I just left it alone. I will be driving down to Virginia this spring though, so I would kinda like to get it working again.

The problem that I started having is, you can turn cruise on, but when you hit the set button, the car keeps accelerating with no way of stopping it. Hitting the breaks doesn't turn cruise off, pushing the on/off button on the steering wheel doesn't turn cruise off.

What I had to do when this happened was put the car in neutral and kill the engine, then pull the car over and pop the hood. What I would have to do is go to the throttle body and pull the throttle control cable that runs to the cruise module back out, then start the car and keep going.

So basically the module keeps pulling the throttle cable even after you have hit the set button and the only way to stop it is to stop the car, pop the hood and pull the cable back out at the throttle body control.

So my question is, what component is most likely to blame? Should I put a new module in it? I looked on Rockauto and there is this cruise switch (ACDELCO # 22712549). Could that be causing this? New modules are kind of expensive, but I have found some fairly cheap ones on ebay, and I may take a look at junk yards near my house too.

Thoughts, ideas, answers??? Thanks!

[fdryer]

Well, for one thing, you have a dangerous condition if this leads to a runaway. Something went wrong and before delving into the electronics, perhaps looking things over mechanically may help. Stuck cc switches, faulty brake switch, sticking cc cable, etc.. There's an extensive check list/flow chart for troubleshooting that may take some time before this gets fixed. Start with the ON/OFF switch as this should turn on/off cruise control.

If it sticks in the ON position and you're unable to turn it off, this may be one of several issues. The set/accelerate button is another possible sticking issue. Last is the brake switch that disables cc at any time when braking. Test to be sure the brake lights turns on/off when using the brake pedal.

[macman90]

I can verify that the brake lights do work properly.

I was wondering if it could have something to do with a stuck cc cable, but if that was the issue I would think instead of continued acceleration, I would simply not be able to get the car out of cruise because the cable would not release from where it locked in. Its the fact that the module continues to open the throttle more and more after I hit the set button that makes me curious about exactly whats wrong. If it was staying where I set it and just simply not releasing when cruise is disengaged it would simplify the issue.

I will take a look at the cruise on/off switch tomorrow. I can't remember if the light stayed on even after I turned it back off or if the light turned off. If the light stays on, that may indicate a problem with the switch, but I have no intention of driving the car around trying to use the cruise for the purpose of diagnosis, I'm just gonna take a look at what I can with the car parked.

[ssicarman]

Originally Posted by macman90

Awhile back my cruise control stopped working and at the time it wasn't a huge issue so I just left it alone. I will be driving down to Virginia this spring though, so I would kinda like to get it working again.

The problem that I started having is, you can turn cruise on, but when you hit the set button, the car keeps accelerating with no way of stopping it. Hitting the breaks doesn't turn cruise off, pushing the on/off button on the steering wheel doesn't turn cruise off.

What I had to do when this happened was put the car in neutral and kill the engine, then pull the car over and pop the hood. What I would have to do is go to the throttle body and pull the throttle control cable that runs to the cruise module back out, then start the car and keep going.

So basically the module keeps pulling the throttle cable even after you have hit the set button and the only way to stop it is to stop the car, pop the hood and pull the cable back out at the throttle body control.

So my question is, what component is most likely to blame? Should I put a new module in it? I looked on Rockauto and there is this cruise switch (ACDELCO # 22712549). Could that be causing this? New modules are kind of expensive, but I have found some fairly cheap ones on ebay, and I may take a look at junk yards near my house too.

Thoughts, ideas, answers??? Thanks!

You have found your problem. You don't really need to look further until you find out why the cable is sticking and keeping the throttle open. You have a problem in the cable or module area.

[macman90]

Originally Posted by ssicarman

You have found your problem. You don't really need to look further until you find out why the cable is sticking and keeping the throttle open. You have a problem in the cable or module area.

I do think it is most likely in the cable or module area, but as I mentioned in my reply to fdryer, the fact that the module continues to pull the cable and open the throttle more and more even after I push the set button makes me curious as to problems in the area of electronics i.e. the module. If I was able to set my cruise and have it stay at the set speed but I was unable to release it then I would lean towards cable, but since the car continues to accelerate with no way of stopping it except the one I detailed above it makes me lean more towards the module.

[Mom'sSaturn]

Another question: Is the L4 also drive by wire, like the V6? The reason I ask is I'm willing to try something to help out here. On my way to work tomorrow I will turn off my cruise on the steering wheel while holding the resume button in. My hunch is his resume button is stuck. If I do keep accelerating, then we know that resume over-rides the on off switch. And yes, my CC works fine. I will post the result tomorrow.

[macman90]

Yes I believe it is drive by wire. I will be interested to hear the results of your test, I hadn't thought of that but it sounds possibly plausible. If it turns out to be that I can replace those switches for 20 bucks on ebay and that would be great.

[Mom'sSaturn]

Sorry Macman, I tried a number of times switching the cruise off while holding in the resume button. The engine would surge for a split second then slow down. Sorry, but you will have to dig deeper!

[Jonnyferrari]

Super scary, sounds like you need to start a lawsuit there. But really, this freaks me out.

[macman90]

I haven't heard of this being a very well known problem with the L series, plus the cost and duration of any legal action would more than likely far outweigh any perceived benefits. It this point based on what I have seen in this thread and my own messing around I am willing to bet its the cruise module. Does anyone here know how easy it might be replace that part myself? It looks like it would probably be pretty simple, and I can pick up a used module on ebay pretty cheap.

[born again]

Originally Posted by macman90

Yes I believe it is drive by wire. I will be interested to hear the results of your test, I hadn't thought of that but it sounds possibly plausible. If it turns out to be that I can replace those switches for 20 bucks on ebay and that would be great.

The L4 is NOT Drive-by-Wire. It has an old-style throttle cable. It also has a cable between the cruise throttle actuator by the firewall to the throttle. The cruise on a DBW car is very different in that the throttle signal from the ECM is controlled by the software speed control loop instead of the accelerator pedal. The throttle is actuated by the same motor for both functions. This sounds like a faulty throttle actuator module or cable problem to me. A sticking cable might do this as it would fail to return to lower throttle openings. You could try to lubricate and free up the cable.

How keen are you to experiment with this? Practice shutting down the engine while on the fly (not as dangerous or scary as it sounds).

[macman90]

Originally Posted by born again

This sounds like a faulty throttle actuator module or cable problem to me. A sticking cable might do this as it would fail to return to lower throttle openings. You could try to lubricate and free up the cable.

I would agree on the sticking cable, but as I said before, the issue isn't that it locks the cruise and fails to unlock, its that it fails to lock in the first place and won't shut off. Instead of holding the throttle at the position it is in when I press the SET button the throttle actuator module continues to open the throttle even more, continuing to pull on its cable connecting it to the throttle. So, it would seem for some reason that the module is simply failing or something is preventing it from realizing that it doesn't have to continue retracting the throttle cable once it reaches the point I had the throttle open to.