P0755 - Shift Solenoid B

prienzo · Post by **prienzo** » 29 Jul 2010, 18:12

Hey guys, I've had this problem for awhile now and I'm hoping to finally solve it. Thanks to all who have helped me so far. Here is the summary of what happens.

Every few weeks, I get a CEL and flashing arrow. After driving around in 3rd gear for a few miles or so, the car finally reverts back to driving normally. I reset the CEL light and the car is fine for a few weeks. Then, it all happens again. The code I pull is P0755, Shift Solenoid B Malfunction. I have a few questions about this.

a) Am I doing any more damage by letting this cycle continue?
b) How probable is it that replacing the shift solenoid would solve this?
c) How much should I expect it to run me to have the shift solenoid replaced
d) If I have one replaced, should I have all of them replaced?

Thanks so much guys.

Post by **jblackburn** » 29 Jul 2010, 20:15

What year is this car? The 94's and early 95's used crummy solenoids that are prone to failure more often.

Do you get a code for "incorrect gear ratio" as well?

Next time it happens, try the rowing the shifter trick 15-20 times in quick succession from P to L. Then reset the code and see if it re-occurs.

I would not keep driving it like this; starting off in 3rd gear causes a huge amount of stress to the torque converter and transmission internals. It's like starting a manual car off in 4th gear and slipping the clutch like crazy til it gets going. Only without that terrible burning clutch smell.

I don't know how much it would cost you to have this replaced, but the solenoids themselves are about $130-150 each. I would replace them both while the cover is off, because my car has a flaky one itself. Knowing my car, once you replace something in the general area, the next one will go bad very soon, so I've learned to do everything while I'm in an area.

prienzo · Post by **prienzo** » 30 Jul 2010, 06:04

Thanks for your response. It is a 98 S70 GLT. Also, I have recently had the PNP switch replaced which did not cure the problem.

Post by **jblackburn** » 30 Jul 2010, 08:53

OK, I think you are on the right track looking to get the solenoids changed out. Call around and get some estimates - I would recommend going to a Volvo indy mechanic for something like this. It's doable yourself if you're any good with a wrench, but if you don't seal the cover back up good, it will leak transmission fluid like crazy.

Just curious, how many miles on yours?

prienzo · Post by **prienzo** » 30 Jul 2010, 11:36

Car has 130,000 miles on it.

Nick Jones · Post by **Nick Jones** » 30 Jul 2010, 15:11

Next time the problem occurs you need to identify if its the solenoid or the trans ecu at fault. I have had both happen in my day job as an auto trans rebuilder,
When the problem occurs you need to check the resistance of the "b" solenoid, the easiest way to do this is check through the wiring from the pins on the ECU. You can find this data out on a wiring diagram. If the ohms reading is less than 30 ohms then the sol is ok and it is the ECU that is at fault.
Hope this helps.

prienzo · Post by **prienzo** » 02 Aug 2010, 13:43

Just got the car back from the dealership for an estimate.
$1100 to replace the solenoids and do a tranny flush. They won't guarantee this will completely fix the problem though
$3500 for a new transmission

I'm going to shop around today and get some estimates on the solenoids. Thanks for the help guys.

prienzo · Post by **prienzo** » 04 Aug 2010, 14:25

Just wanted to post a final update...

Brought the car to Aamco. It seems that although the computer was pointing at the Shift Solenoid, this was not the problem. They told me the problem was that I was losing pressure in the transmission and the solenoids were fine. They opened up the transmission and found that it was beyond repair, that it overheated and blew everything. I am going to have a used transmission (51,000 miles) put in. Thanks for all of the help guys.