2004 saturn l300 trans

[sunniewally]

I have a 2004 saturn l300 with the v6 and about a 160,000 mi on it. the engine light with the wrench comes on and it starts shifting hard. if I shut it off for a minute and restart, the light goes off and the transmission shifts smooth again till it comes on again, which may vary in number of miles. some say its a solenoid in the trans. if so what is the purpose of that solenoid and why does it work just fine after you restart it? could it be some goofy sensor or some external computer problem?

[Jeremy airjer W]

find out what codes are are causing the check engine light to come on.

If there is a fault detected in the transmission it will go into a limp mode. In your case it sounds like it is jacking pressure to minimize slip. Turning the car off "resets" or "fools" the computer into thinking the problem has resolved itself and it shifts normally until the problem shows itself again.

It does no good to speculate without knowing what the code(s) are.

[sunniewally]

I was told it needs a solenoid in the transmission, but I was wondering what was going on to cause the harsh shift and then is okay after you restart. so the trans is slipping at some point and the solenoid is compensating for the slip? wouldn't that happen on every time it has to shift?

[Jeremy airjer W]

so the trans is slipping at some point and the solenoid is compensating for the slip? wouldn't that happen on every time it has to shift?

If the computer is seeing a fault it will go into a limp mode. In your case it sounds like the limp mode is to jack up pressures and engage gears faster (harsh or hard shift, bangs into gears). It will continue to do this regardless if the problem is present during the current drive cycle.

When you shut the car off and restart it the computer starts over. It will operate the transmission normally until the fault occurs again. It will then go into limp mode and continue in limp mode until the next key cycle.

[sunniewally]

thank you!