2004 Saturn Ion Transmission problems

My saturn ion wont go above 20mph, when I first start it, it’ll go up to 40-50mph then just slow down to 20mph. The previous owner said it needed a transmission module which he put in it. When I first bought it, it wouldn’t go past 20mph, took it to shop & they said it needed a new trans, but when it took it home, mine you I expected it to go 20mph it went up to 60mph without any problems. Any idea what could be the problem? I don’t wanna buy a new transmission without ruling out everything.

It sounds to me like it’s having an intermittent tranny problem that’s causing it to go into “limp home” mode. But it needs to be diagnosed by a tranny shop to be specific. Forget about what the prior owner said.

I strongly urge you to go to a reputable independently owned and operated shop. I strongly urge you to avoid the chain stores, especially All Automatics Must Come Out (AAMCO). You could go to AAMCO with a flat tire and they’d probably tell you you need a new tranny.


That’s actually not very far-fetched!

There are a lot of transmission failure with these cars

Well of course it does . 121000 miles and 13 years old what would you expect ?
The OP did not state mileage and said the car did not operate properly when they bought it so no surprise here.

throttlebody is not drive by wire.17202005_Alternate1__ra_p

May be electrical. Crawl under and over, find every plug and connector going to and from the transmission, unplug, inspect, spray liberally with electrical contact cleaner and plug everything back together. Worth a try. I had this kind of problem with a 93 Plymouth Voyager and every shop wanted to sell and install a rebuilt transmission. I fixed it just like I said above. I smelled a rat because there was no progression to the unacceptable condition. Last night it worked normally, this morning it won’t go above 20 mph.


What I don’t understand is that when I turn it on, it’ll be okay for about 5mins then it’ll slow down automatically and won’t go above 20again. I press gas peddle & it’ll like limp forward, but not go above 20mph. It’ll shift once then just not want to shift anymore.

Im only 19 and this is my first car. I’ve already put around $1,500 fixing everything else. A shop I took it too said it needed a new transmission, but I gave them my car with less than 100,000 miles, and when I got it back it had 123,000 miles

23k miles? Get a lawyer.


How long did the shop have it when they put 23k miles on it?


Average 50 MPH to get 23000 miles would take 46 days at 10 hours a day. Me thinks something does not add up.

They had my car from Early days if September till Middle of November

If the car acts and sounds normally otherwise, just gets itself into a mode where it won’t go over 20 mph, that sounds like it is going into limp mode. The computer control has determined there’s a problem with a safety system, or thinks engine or transmission damage may occur if allowed to be driven at normal speeds. Either way, it only allows 20 mph max, just fast enough to limp back home to your driveway or to your car repair place. It’s a feature in other words.

When it goes into limp mode, it does that for a reason, and it saves the reason in the computer’s memory. As long as you don’t disconnect the battery, that info will stay there. The proper way to address it is to read out all the diagnostic codes from the memory, which might include from the transmission module. From that info a shop can determine what the problem is.

From what I can tell, you’ve already had a shop do the diagnostic, and they told you it is a transmission problem that can’t be repaired. So you have two options: Either follow their advice, or if you don’t trust it, seek out alternate advice from another well-recommended shop in the area.

If you are looking for some guesses is all, could be a faulty transmission solenoid, damaged transmission clutches, a faulty engine crank sensor, faulty fuel injector, etc etc etc …