Code: Incorrect Gear Ratio?

[squeaky3]

This is to update all who kindly responded to my INCORRECT GEAR RATIO problem:

Everything I was advised to do except changing the fluid I did, making no difference. I took the car tio Eagle transmission, which after keeping it 4 hours, called to tell me they couldn't read the code or communicate with the vehicle (whereas an auto parts store scanned it with the small OBD II successfully. Apparently Eagle used the larger, Global OBD II, which doesn't work).

Next I took it to AAMCO, which after 1 and 1/2 hours determined the labor charge would be $267, though AAMCO has no idea what's wrong with the car and what it needs to fix it. Makes no sense to me.

Then I took it to A+ Transmissions because it offers a $19.95 oil and filter change, etc,, but after enptying the oil saw it was black and smelled burnt, which the tech explained indicated the clutches were badly worn and needed replacemebt, to the tune of a $689 deposit and upwards of $1500.

By the way, I called Cottman transmissions and over the phone, sight unseen, and not even asking what the code read, said repairs would be $1500 for starters.

In the meantime, I replaced the computer module for the transmission with one of the same number, 7.3, I got at a junkyard that was sitting in my garage. Lo and behold, the check engine light, arrow, and blinking green light returned to normal, i.e. the check engine light and arrow disaapeared and the blinking light became solid again -- for as long as it took to drive from my house to he corner, then they returned. I went to the auto parts store to get and read the code again. This time I got a different code: while the first one was PO730 (Incorrect gear Ratio), the new code is PO500 (vehicle speed sensor), which, of course, could have been on the junkyard module. There are no other codes, including the original, plus, the car seems to drive better: while there's still no distinction between drive and third, there is a definite 4th gear, and there is more power. But what happened to the original code? what does vehicle speed sensor mean? And maybe, just maybe, it's not the transnission that's bad, IT's THE COMPUTER MODULE. CAN ANYONE MAKE ANY SENSE OF WHAT'S TRANSPIRED AND SUGGEST WHAT TO DO NEXT?

Thanks.

squeaky3

[squeaky3]

This is squeaky 3 again. I forgot to tell you that I took the car to A+ Transmission. They were going to change the transmission oil. They dumped the old oil, showed me it was black, and said it smelled burnt. They said that means the clutches are worn down and that if they replaced the oil with new, because the new has detergent in it, it would further erode the clutches. So they recommended NOT replacing the oil and just put the old oil back in. They want me to return to find out what's wrong with the VSS and probably replace it. For a deposit of $689... What to do? Somebody please respond to this and my previous post. I don't know what to do.

[squeaky3]

I got a lot of responses to my initial post, but now that I've done what was suggested and more, and the problem persists or is worse, I'm not getting any responses. You guys are leaving me hanging. Turns out the car is NOT in limp mode, as was suggested; turns out also that I put in the wrong computer module: Because both said 7.3 in large numbers I thought they were the same, but the original number on the module that gave me the INCORRECT GEAR RATIO reading, P0730, is P 9143128, which doesn't match the module I put in that reads VEHICLE SPEED SENSOR. In any event, I would think if there were a problem with the VSS it would show up in the speedometer, which it hasn't. So I'm guessing VSS pertains to the car the module came from and not mine, though my reading INCORRECT GEAR RATIO no longer appears and the car seems to drive better: whereas before I changed the modules there was no difference betweeen drive, third, and fourth gears, now there's a distinct fourth (low) gear, though drive and third still seem to be the same. In addition, the sluggishness on starting from a stopped position is no longer the case, and the car seems to have more power and zip in drive. But clearly I still need help, and you guys seem to have abandoned me.

[BigRed]

Is the burnt fluid still in there? I can't imagine that is doing anything but making the situation worse. , I would replace it ASAP...preferably several times spaced out as much remains during drain and fill. What do you got to lose, everyone already wants to charge you thousands...

ATF drain and fill is no more difficult than oil change, just need a bigger wrench (24mm) and a funnel with smaller end. There is no serviceable filter.

I'll try too get picture this evening of sensor I have unplugged that got everything back to normal on my '96 855t, albeit with a persistent P0500 (but shifts good!). Try it, again...what do you have to lose.

Sent from my BlackBerry 8530 using Tapatalk

[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.