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Saturn Problem

A neighbor has a 2000 Saturn

Wagon 6cyl with around 100kmi. As I understand it, as she is driving mainly at HWY speeds a dash worning light in the shape of a wrench comes on and at that time the car will start jurking as though the transmission is shifting up and down between gears. If she pulls to the side of the road and turns the car off for a while and then continues on it will work fine until the next time the wrench light comes on. I sounds to me like this car may have some kind of electronic shifting and it is failing is some way. Dose this sound like a possibility.Any suggestions.

The little “wrench” light is likely the “check engine light” (aka CEL; malfunction indicator lamp - MIL).

Whatever is going on with the car is being picked up by the diagnostic system and is storing a “diagnostic trouble code” (DTC) in the engine’s computer. The first thing to do is have someone hook it up to a code scanner to see what codes are stored there. Many auto parts stores will do this for free. If she does this you can post the codes back up here (but the actual codes, e.g. P0123, not what anyone says about them).

The problem could be in transmission control, but it could also be in the engine. The DTCs are the most sensible place to start. Either way she should do something with it soon as some of these problems can be small unless ignored - in which case they turn into much bigger problems.

Note: if the wrench light is flashing at her she should stop driving the car immediately as continuing to do so stands a good chance of serious harm to the engine.

saturn hastwo CEL lights. the wrench ususally can only be read by a dealer or some one with a scanner. Auto parts stores can read the other check engine light or “service engine soon” light on saturns but not the wrench codes. MY suggestion is to change the engine coolant temp sensor. the OEM one was made from resin and will crack over time and cause all kinds of engine woes. Its a $9 part and easy to change. make sure you get the brass tipped one.

I have the same car with the same problem. Everything fixes itself (temporarily) when I shut off the car and wait a few seconds. But it always returns eventually. My mechanic couldn’t find any codes when he scanned it, and suggested that the dealer may find something. SO, I finally took it to the dealer when the wrench light came on and had them scan it while it was still running.

They also said that their were no obvious problems, except with the computer itself. They informed me that this car actually has three computers (one for the drivetrain, one for the body/accessories, and the third for something else (I forgot which)). They said that something is wrong with one of these computers, such that it isn’t communicating with the others properly. This would cause the jerky transmission problem, in that miscommunication of when to shift gears, from computer A to computer B, could produce the problem.

The remedy, they said, was to bring it in and have the computers wiped and re-uploaded with everything. The analogy was like an old PC that needs to be wiped and the operating system re-installed.

As it is now, they can’t tell if it’s a problem with the transmission or just with the computers. But the computer has to be fixed first.

I have no idea how valid this information is - it’s just the advice I got from the Saturn dealer. I’m going to attempt it, and will update / reply again later.

Please do let us know how this turns out; I have a similar problem with my 2002 Saturn SL2. Took it 2 places and was told 1.)the transmission needs rebuilding ($2300) and 2.)the valve body needs replacing ($1200). Several people suggested it might be the computer. I called another transmission place that said immediately, “It might be the computer.” He asked if the “service soon” light was on, which it was. This shop is not convenient to me and I haven’t been yet; I will go there since they are the only ones who seem at all interested in checking the computer idea. In the meantime, the light went out and the car is running better. Makes sense that this is somehow tied into the computer. So let us know how yours turns out. And good luck!

UPDATE to my previous message

The Saturn dealer has the car, and have found the problem. They originally thought that the computer had to be re-programmed (see above), but when they did so, it failed to ‘take’ the reprogram. They, then deduced that the wiring harness for the transmission control module was faulty, and had sent off to get the parts. This was going to be a $1200 repair.

They got the parts in, and installed it, but the car would not take it, and the old one worked better. The head tech guy did some more detective work after that and found that the transmission’s pressure control solenoid valve is going bad (almost gone). That explains the jerky transmission, and the totally destroyed transmission fluid from the bottom (top is OK). The valve will be replaced in two days.

The transmission is still fine, but if anyone is having this problem, don’t wait until it happens too frequently, as this is a signal that the solenoid valve is deteriorating. My wrench light w/ jerky transmission was happening about once a week over the summer, then around two weeks ago it was happening every time I drove the car.

So, this is the latest news on this problem. If it is anything other than what I described here (the pressure control solenoid valve), I will update again. For now, I’m looking at about $950 for the part + labor.

Let’s hope this solves it!

quick update. the solenoid valve was it. Just got back from a 2000+ mile road trip and had no problems at all. the cost was just over 900 clams.

Good to hear it worked out OK if not cheap.