SaffC70 Posted January 21, 2010 Report Share Posted January 21, 2010 I would see this clear as day, but the thing that gets me is it's intermittent. If there was a mechanical failure, I would think the problem would be all the time. I'm going to look at it this weekend, but was trying to pick some more brains, thinking whether the intermittent speedo had anything to do with the intermittent tranny issues. Reading the manual it seems to me like they could go hand in hand. It may be worthy to note that once the codes are cleared, and the shift arrow is not lit, the winter mode button functions properly, though it does not take long for the light to come back. As well, the sport and economy modes both are functional. yeah i would clear the codes but they came back later, i wouldnt count out that the transmission is bad IMO Link to comment Share on other sites More sharing options...
mojojo Posted January 30, 2010 Author Report Share Posted January 30, 2010 yeah i would clear the codes but they came back later, i wouldnt count out that the transmission is bad IMO So, I took a look at this the other day, and then again today. My opinion, the rough shifting/sticking is directly related to the speedometer's operation. And, because my speedometer is intermittent, my transmission intermittently sticks in first. I've come to this conclusion based on a few observations, whenever my speedometer is operating, the transmission shifts smooth as silk, when it is not working properly the problem is always present at initial start. Looking through the documentation linked above, I've seen that the TCM requires input from the speedometer sensor to determine shift points. As the TCM reads the input, it controls the solenoids to shift to the appropriate gear. Now, my problem, I can't determine/find a way of troubleshooting the system statically without the Volvo tool(s). Can anyone guide me down a good trouble shooting path, without requiring any special tools/scanners? Link to comment Share on other sites More sharing options...
Guest west Posted January 30, 2010 Report Share Posted January 30, 2010 Dude. If your swapping tranny parts between turbo/non turbo this could be it. A GUESS AT BEST. ECON/SPORT switch could be your problem. Transmissions are metal,,Buttons are plastic. I'm not a rocket enginer but iv'e fixed window switches with GUM. Check fuses and try the paper clip 'ground' on the switch. My traction controll switch isn't working now, but will see some gum soon. good luck. Link to comment Share on other sites More sharing options...
lclark96 Posted January 30, 2010 Report Share Posted January 30, 2010 Hey, Did you try and change out all the internal trans. solenoids? could be a solenoid going bad..? maybe.. just a shot here.. Link to comment Share on other sites More sharing options...
mojojo Posted January 30, 2010 Author Report Share Posted January 30, 2010 Dude. If your swapping tranny parts between turbo/non turbo this could be it. A GUESS AT BEST. ECON/SPORT switch could be your problem. Transmissions are metal,,Buttons are plastic. I'm not a rocket enginer but iv'e fixed window switches with GUM. Check fuses and try the paper clip 'ground' on the switch. My traction controll switch isn't working now, but will see some gum soon. good luck. Dude. I don't know where turbo/non-turbo came from. I have three cars, two (including this one) running T5-Rs, and one 95 Turbo for parts. the only part I've used so far was the PNP switch to correct a no start situation. I don't think it is either the sport/econ switch or the winter mode button. Once codes are cleared, and the car is started with no lights on, the up arrow lights according to the winter mode button - ruling out the button. The sport/econ switch operates normally, even while arrow is flashing. I've determined the intermittent speedo is the issue, now I need some guidance on proper troubleshooting of the system. ...just because your car has issues with the switch, doesn't mean that mine does too, besides, I don't like gum. :lol: Link to comment Share on other sites More sharing options...
JordanW Posted January 30, 2010 Report Share Posted January 30, 2010 If your parts cars are 95 or older, try swapping the speed sensors - located on the back of the trans. A simple check to see if the connection is clean would be worth while, just as well, to pull your old one and make sure it is clean and not covered with metal particals. A new speed sensor is only $80 at Eeuro parts or FCP http://www.fcpgroton.com/product-exec/product_id/32414/nm/1994_1997_Volvo_850_Turbo_Speedometer_Sensor/category_id/111 Good Luck Link to comment Share on other sites More sharing options...
mojojo Posted January 30, 2010 Author Report Share Posted January 30, 2010 If your parts cars are 95 or older, try swapping the speed sensors - located on the back of the trans. A simple check to see if the connection is clean would be worth while, just as well, to pull your old one and make sure it is clean and not covered with metal particals. A new speed sensor is only $80 at Eeuro parts or FCP http://www.fcpgroton.com/product-exec/product_id/32414/nm/1994_1997_Volvo_850_Turbo_Speedometer_Sensor/category_id/111 Good Luck I've checked the plug at the sensor, and while the plastic is broken, the metal bullet type connectors have a good fit. I've toyed the idea of swapping the sensor from my parts car, but haven't committed yet since it's a ways away at a relatives house. I think I may run by this weekend and get it for a try. Link to comment Share on other sites More sharing options...
mojojo Posted March 12, 2010 Author Report Share Posted March 12, 2010 Turns out my suspicions were correct. Apparently the VSS must signal to the cluster and TCM reads inputs from cluster. So, no speedo at the cluster means no signal to the TCM, and therefore TCM shift malfunction. I replaced the sensor, simply because I had a known good part, this afternoon - that did not fix the problem, still intermittent speedo. Now, I was just not sure where to go so I started in to an old habit of mine when diagnosing electrical connections, by just wiggling the components and checking to see functions. Eventually a made it to an area to the left of the steering wheel and noticed that if I applied lite pressure that the speedo would begin to function. This had me going. I took the dash pad off and removed the gauge cluster looking for any loose connections I noticed the connection at the top left (looking at the cluster installed) was not connected at all. I checked this installed and still had no speedo. Next I removed the cluster and went to the area I was able to apply pressure to and checked out the harness that gets snaked through the metal on the dash here. I found two wires that wire worn through the conduit showing copper. I did a quick repair and speedo now works - wires must have been grounding here. I made this a permanent fix by running the harness through a piece of heater hose that was split down the middle. This was an easy fix using parts I had, so I'm certainly pleased. ...Only obstacle left now is my radiator fan... Turns out my suspicions were correct. Apparently the VSS must signal to the cluster and TCM reads inputs from cluster. So, no speedo at the cluster means no signal to the TCM, and therefore TCM shift malfunction. I replaced the sensor, simply because I had a known good part, this afternoon - that did not fix the problem, still intermittent speedo. Now, I was just not sure where to go so I started in to an old habit of mine when diagnosing electrical connections, by just wiggling the components and checking to see functions. Eventually a made it to an area to the left of the steering wheel and noticed that if I applied lite pressure that the speedo would begin to function. This had me going. I took the dash pad off and removed the gauge cluster looking for any loose connections I noticed the connection at the top left (looking at the cluster installed) was not connected at all. I checked this installed and still had no speedo. Next I removed the cluster and went to the area I was able to apply pressure to and checked out the harness that gets snaked through the metal on the dash here. I found two wires that wire worn through the conduit showing copper. I did a quick repair and speedo now works - wires must have been grounding here. I made this a permanent fix by running the harness through a piece of heater hose that was split down the middle. This was an easy fix using parts I had, so I'm certainly pleased. ...Only obstacle left now is my radiator fan... So speedo works and trans shifts like butter. Link to comment Share on other sites More sharing options...
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