I just bought a 2002 V70XC with 161K miles with known transmission problems (harsh 1-2 shift, going into limp mode, etc).

I did a fluid flush and the B4 servo cover as well as the adaptation procedure with no luck. Kept getting the same trouble codes and the "transmission service required" message.

I talked to SunBelt Valve Body Builders in Tampa, FL and sent them my valve body for testing. They said it needed to be rebuilt and did so at a cost of $575 offering a 12 month/12,000 warranty.

I installed the valve body, flushed the trans again and used Mobil 1 fluid, installed a magnetic inline trans filter, and ran the adaptation procedure again. It worked fine for about 50 miles and now back to harsh 1-2 shifts, limp mode, etc. I get a P0778 code...pressure control solenoid "B". Reset the code and the trans functions perfectly for a few minutes or a few hours. It shifts smooth, no flaring, no slipping...then the transmission message and the orange triangle and limp mode.

Is it possible the valve body that I just replaced has a problem? Could it be the TCM? I can't keep putting money in the car and if I can fix it, I'll have to sell it as-is and take a loss.

This is my first Volvo so I am trying to learn all I can about them. Hopefully, someone who knows a lot more about these transmissions can shed some light on the subject before I set the car on fire out of frustration!

Thanks in advance!

 

It says here to replace the solenoids?
Drive Line - Howard's Volvo Maintenance

 

The 3 linear solenoids were rebuilt and the other solenoids were checked and replaced as needed when the valve body was rebuilt.

SunBelt Valve Bodies does a lot of AW55-50 valve bodies and they have a special machine that can test them under pressure....the solenoids just aren't tested for a specific Ohm range.

It has me stumped for sure...but I'm betting someone has had the same problem and will be able to offer some advice. Otherwise, I have to take the valve body out and send it back to SunBelt to see if there is a problem.

BTW, Howard's Volvo site has tons of useful info...thanks for the link!

 

I am having shifting issues too, but only once the tranny heats up:
https://volvoforums.com/forum/2001-2...en-warm-62088/
Let me know how you make out.
I am thinking about making the valve body plunge, but I think I have to invest in the vica thingy. What do you think?

 

Well, I'm still having the exact same issue with my Volvo transmission. Here's what I've done so far. I did a trans fluid flush, had the valve body rebuilt, replaced the linear solenoids (under warranty from the rebuilder), installed several Sonnax update kits, replaced the TCM, and finally...replaced the valve body with one from a known good shifting low mileage transmission.

I still get the P0778 Pressure Control Solenoid "B" code and the car goes into limp mode.

I've checked all the ABS sensors, replaced the wiring harness that runs to the valve body, checked all the ground cables, ran additional grounds, and on and on. Unless someone can shed some light on this issue, I'll be forced to sell my Volvo at a huge loss.

Is it possible the ECM is bad? Nothing I've done so far makes any difference...same issues, same trouble code.

PLEASE throw me a bone...any and all ideas are welcome!!

Thanks!

 

Any progress in this? It sounds like a total mystery when I read your post.

 

After spending months trying this and that and a lot of money on the transmission, I come to find out it wasn't the transmission or valve body at all. The computer was getting a signal from the throttle body servo, putting the transmission in "limp mode" even at idle in the garage.


I took the servo apart, cleaned the contacts, applied some dielectric grease, put it back together and the transmission shifted perfectly.


I sold the car not long after (due to sheer frustration) and the guy who bought it is STILL driving it and had ZERO issues with the transmission. If I hadn't invested in the Volvo diagnostic software and DICE, I wouldn't have ever figured it out.


I wonder how many people buy transmissions or valve bodies because they THINK they are bad? Volvo may make a nice vehicle but I'll never buy another one...

 

It's Volvo's fault you played the guessing game by throwing parts at it instead of having it diagnosed? An ETM won't set trans codes.

 

I DID have it diagnosed by 2 different shops or else I wouldn't have put a rebuilt valve body in it. This may have been my first Volvo but I'm not stupid, I've turned wrenches for 30+ years. I don't "throw" parts at a problem, hoping I come across an answer.


Even after replacing the valve body, I still kept getting the same code. And YES, it WAS the throttle body servo causing the transmission issues. This was also confirmed by a Volvo Dealership in Knoxville, TN. Volvo's are programmed IF there is an issue with the throttle body servo, the trans goes into limp mode as a "safety feature".


You can believe what you want, it was the TB servo causing the transmission codes, making me, 1 dealership and 1 transmission shop think the valve body in the transmission was bad.

 

The throttle may have fixed it, I have seen them cause problems without setting codes. But limp home mode or not, a throttle won't set a fault code for a transmission solenoid.

 

Where’s the servo for the throttle body? Or do you mean throttle body?

I have done all of what u did, changed the valve body, the tcm, reprogrammed it and so on, but i cant get my car working...i get these two codes- P0778 and P1618...i even changed the harness in the gearbox but it will just continue go in to limp mode

 

Where's the servo? I'm having the same problem. Already did the flush, bough a new valve body, I did the updates and everything, and it still having a rough change from 1 to 2 gear.

 

Did you put the transmission in adaptation mode (or have someone else with VIDA turn that function on) and complete that cycle - to have the TCU learn the best way to shift?

In answer to your question the "servo" is the throttle body.

 

I just bought it on amazon. As soon as it arrives I'll be doing that.

 

At that mileage and if it was never flushed it may need new friction disks. Very common for 01 02s' to literally wear out
AND yo all have described exactly how the vehicle operates with worn out disks.

Which means a transmission rebuild. Which IMO is worth doing but most tranny shops will not have a clue as to how to do it.

As always and sounding like an ad,...LEVEL TEN in NJ does an incredible job rebuilding Volvo transmissions to better than new condition. I have used them in the past and every vehicle they have rebuilt has had NO issues whatsoever.

So many people play with the solenoids because they are accessible when the transmission is worn,...GENERICALLY WHEN A SOLENOID HAS AN ISSUE THE TRANSMISSION WILL NOT SHIFT WHATSOEVER. IT WILL LOCK UP. The vehicle will not move. As a rule. So many early Volvo's and especially the XC Cross Countries had issues that can be solved by a good rebuild. It is worth doing but be aware that you now have an vehicle that if totaled yo will never recoup your costs from an insurance company, HOWEVER you vehicle will keep going after the rebuild for years saving you thousands over the cost of new. The only drawback to this kind of thinking is your older Volvo does NOT have the safety front auto braking systems and considering that it may be worth it to purchase new for the 30 - 60 k cost.

Good luck,...for your info I have currently 3 volvos' all with rebuilt trannies, I purchased the vehicles on craigs list and from local salvage yards for under 500 each, and sent the trannies to Level Ten,.....as compared with financing a new Volvo,...my cost averaged per vehicle is now less than 1500 excluding insuance in total for the 3 of them, and I get to choose which one to drive depending on MY needs. And yes sometimes one of em needs some maintenance but it is great to be able to not be under the pressure of having only one vehicle.