Code: Incorrect Gear Ratio?

[jimmy57]

What year model is the car? you have zero car info listed.
Depending on what year model there are differences in the vehicle speed sensor. ->95 gets info from speedo which gets its signal from a trans final drive case mounted sensor.
96-> uses a digital signal type sensor. From what you listed I think you have a 93-95 and your junkyard TCM is a 96-98 and it saw the wrong trans speed sensor signal but otherwise is wired the same to trans.

BUT, the incorrect gear ratio code is set due to the TCM commanding solenoids in a pattern that should give a particular gear and then it knows the gear ratio by computation of VSS and engine or trans input RPM.
You should have 3 gear changes plus what would feel like a shift when it locks the torque converter once in 4th.
That would be the 1-2 shift, the 2-3 shift, the 3-4 shift for the three gear changes and then once 52-54 mph is reached with low throttle application on level ground the torque converter lock will be the 4th "shift".
You could be getting into 3rd only. The TCM would be commanding the solenoids for the 4th gear shift but the ratio is that of 3rd gear and code sets.

[squeaky3]

This is a 1995 850 GLT wagon. With only 125,000 miles on it. To bring you guys up to date:

For some reason I don't remember, I decided to replace the computer module with one I had in the garage, thinking it might fix the problem. Well, Incorrect Gear Ratio did, indeed, disappear, but in its place Vehicle Speed Sensor appeared. Turns out I read the wrong numbers and they were different modules. However, the car ran amazingly better, with more power, and a definite distinction between the gears, whereas before they all seemed the same. So I replaced the second with the original module and took it to a mechanic for a free diagnosis. He changed out the speed sensors, the Incorrect Gear Ratio problem remained, and he told me it was internal, i.e., I need a new transmission. In fact, he said the check engine light would return at 40-50 mph, but it came back at 30. When I got home, I changed the module to the second one, thinking if he put two new speed sensors in, surely that (Vehicle Speed Sensor) code would not reappear. But it did, and I don't understand how that's possible -- unless he put used speed sensors in there, put the input where the output should be, or got the wiring or pig tails confused. (I also can't figure out why he would put two, at least $60 each sensors in, and not charge me for the parts even -- unless he had them lying around and they don't even come from a Volvo, let alone a '94-'97 850.) As usual, any help would be very much appreciated. Thanks.

[squeaky3]

I don't understand 90% of what you wrote, but now that you have my update, you can respond as if I don't know anything about this car, not to mention cars in general. I'm about as knowledgeable as the little old man or lady who knows only where the gas goes, and barely that, which I almost am.

[pkc303]

I think changing the fluid is the first and foremost item on your table. Have you done that? Then worry about which solenoid needs to be changed. Trust the guys on this board, if they say change fluid, you can bet they are correct.

Keep us posted.

[squeaky3]

Mine is a 1995 850 GLT wagon. Since I first posted my problem, the flashing arrow and light are still there and the green economy light still blinks. However, the car continues to run better than it ever did before the problem started and I changed the computer. I can still change the fluid if youn guys think I should but I've been warned NOT to change ALL of it. I will wait for your reply. Thanks.

[pkc303]

That is correct, just drain and replace. Keep track of how much comes out, and put that much in. Should be close to one gallon. Then drive 50 or so miles, and do it again. After about three drives, you should be just about completely changed.

The other thing is get it original computers back in the car. And make sure you have Volvo parts (speed sensors) in the car. It will make diagnosis much easier.