850 Transmission in Limp Mode

[boosted5cyl]

I dont think the VAG-COM software will work. Ive had no luck with the "UBD2 icon" in VAG-Com if thats what you are thinking of. You can use the VAG cable with VOL-FCR however. Only caveat is that VOL-FCR will only look at COM1 so be sure that you have your VAG-COM virtual serial port setup as COM1 in device manager.

I wonder if something got stuck in the transmission fluid cooler. Maybe bypass it and go for a short drive?
Other than that it might be worth doing a line pressure test as documented on page 8 of this PDF: http://www.volvoclub.org.uk/tech/servic ... gnosis.pdf

I have no idea how much such a pressure gauge costs though.
Maybe pump is on the way out? Im not sure where the filter is in this AW tranny, or it if even has one inside but if it exists the tranny needs to come out to gain access to it I would think.

/edit. Here's a transmission\oil pressure gauge for a little over $30 + shipping. Don't forget to buy it though the MVS link
I know nothing about it so buy at your own risk.
https://www.amazon.com/Advanced-ATD-5550 ... B000OUZBZ0

[boosted5cyl]

Also, with the TRACS\ABS warning light, I wonder if you have lost a signal from a wheel speed sensor? It varies from model to model but I believe some take their speed reading from the transmission and others from the ABS sensors. In either case, a bad signal from a speed sensor would definately confuse the transmission.

[1800ES]

Thanks for all the suggestions! I am not driving the car at all right now, so driving it and clearing codes as I go probably isn't going to happen. My commute is way too much stop and go driving and I don't want to put any more strain on the transmission trying to get moving in 3rd gear. Not to mention, I don't feel safe trying to get through some of the intersections at a snail's pace. If it makes any difference, it does seem like the code only reappears when the engine/transmission have gotten warmed up.

I definitely would like to run through a bunch of the diagnostic tests spelled out in the write-up from the UK site. We've already printed that whole article out for reference. As far as checking the filter... Where exactly is it located? I'm looking at an exploded parts view of the transmission on volvopartswebstore.com and I don't see anything that's labelled as a filter. If we get in there to check it, does the filter get cleaned, or does it have to be replaced? If so, where can I buy a new filter? I don't see one listed for sale on any of the usual parts sites.

Unfortunately, I can't afford to dump any more money, or worse, time into trying to get this thing fixed right now. I'm in the middle of a DIY home renovation and I've wasted multiple days of what could have been progress on the house, only to get nowhere with the car. So it's going to get parked on the side of the garage now for at least a couple weeks until we can finish rough-in and get through inspection with the township.

To answer a few more comments, I'm not trying to use VAG-COM itself, but I am hoping to at least be able to use the cable. I definitely want to have VOL-FCR up and running when we get back to trying to solve the problem.

The ABS/TRACS lights did not return during the last test drive. I'd like to think replacing the ABS module with one rebuilt by MattyMoo has at least eliminated that problem. Speaking of which, I need to get my old one in the mail to him...

If anyone has further suggestions, I'd love to hear them. I'll post an update when we are able to spend some more time trying to resolve the problem.

[MoVolvos]

What was the color of the Trans fluid when you flushed it?

Is this the hose you flushed it from except for the older style clamp?


What did the STUFF on the Magnetic Drain Plug look like?

Did the coolant ever make it into the Transmission from the Radiator?

Blessings,
BKM
-

[dbeckwith]

Try driving it with gear selector in 3rd and see what happens. It won't fix anything but you may be able to narrow the search.

[BigRed]

If driving is out of the question due to safety reasons, how about running it on stands...or even just idling in Park? If it's debris clogging, I'd still expect that to happen. If it were a wheel sensor, then I would expect it to not happen. My '96 was still suffering Limp Mode after redoing ABS Module and replacing Solenoids. There's a sensor on top of tranny I disconnected, shifts fine ever since.

I have a $5 eBay serial VAG-COM cable that works with VOL-FCR.

If it becomes too much of a headache...I'd like to have a Platinum Edition!

Sent from my BlackBerry 8530 using Tapatalk

[1800ES]

What was the color of the Trans fluid when you flushed it?

Is this the hose you flushed it from except for the older style clamp?


What did the STUFF on the Magnetic Drain Plug look like?
-

The hose in the video is the one we used to flush the transmission. The fluid that came out was a brownish red, but didn't smell burnt. After about 10 quarts it was a nice red color. The drain plug had some very, very fine metallic particles on it (more the consistency of flour rather than larger particles), but not what I'd consider a very heavy build-up.

I have a $5 eBay serial VAG-COM cable that works with VOL-FCR.

Is the VAG-COM cable that you have a USB or serial? I'm hoping you say USB because that's all I see listed on Ebay. I'm tired of waiting for my boyfriend to get off his butt and get the VAG-COM cable squared away. For that price, I'd happily buy a cable and be done with it, but does VOL-FCR offer better diagnostic info than just the standard OBDII codes? I hate the idea of spending close to $200 to buy it just to end up with a really expensive, glorified code reader that's still just going to tell me P0734. I see that is has a button for the transmission, but what does it do? Does it run through individual tests of various components, like the solenoids, speed sensor, etc?

[BigRed]

My cable is serial, DB9 connector. VOL-FCR was able to say there was a TCM fault, but was unable to decode it. I don't recall specifics, it may have given some HEX values beyond the P code, but was only "evaluating" it, so no support to get fault added in to be decoded.

I wouldn't spring for real VAG-COM cable unless you have a VAG car too, which I do (though I want to replace it with another 850).

Sent from my BlackBerry 8530 using Tapatalk

[MoVolvos]

What was the color of the Trans fluid when you flushed it?

Is this the hose you flushed it from except for the older style clamp?


What did the STUFF on the Magnetic Drain Plug look like?
-

The hose in the video is the one we used to flush the transmission. The fluid that came out was a brownish red, but didn't smell burnt. After about 10 quarts it was a nice red color. The drain plug had some very, very fine metallic particles on it (more the consistency of flour rather than larger particles), but not what I'd consider a very heavy build-up.

If you have exhausted everything and the next step is to sell the car or rebuild the transmission try this fluid. Just flush a total of 8 quarts. If it works or improves a great deal you know that your transmission is getting old and nothing else.

The 714 20W
http://www.pelicanparts.com/catalog/sho ... o_pg10.htm

I believe you used this method but just 8 quarts is all you need to do. You can drain and fill in between rather than fill as you flush like this video as it is easier and don't allow the pan to be empty.



Blessings,
BKM
-

[1800ES]

I wouldn't spring for real VAG-COM cable unless you have a VAG car too, which I do (though I want to replace it with another 850).

We do have a VW Jetta, so the VAG-COM is definitely something we want to keep.

Someone pointed me in the direction of an inexpensive VOL-FCR cable/software package so that's already been ordered. When it arrives, and when the house is through inspection, hopefully the software will help shed some more light on the problem.

I'm not ready to write the entire transmission off just yet as it shifts beautifully through all the gears before it warms up and throws the code. If the transmission itself was shot, I would expect to have problems at all times. We'll see what VOL-FCR has to say, along with the diagnostic tests in the UK write-up.

My absolute last resort will be to take it to a mechanic, but I trust mechanics even less than I trust the transmission in this car.