Gear Position Sensor

barrylay · Post by **barrylay** » 22 Feb 2010, 16:23

My 97 850 s/w can be shifted into reverse or park while the car is driving, but the car cannot be started (at a standstill) if I have the gear shifter in Drive or Reverse. Volvo has told me I need a new Gear Position Sensor. My Questions are:
1) Does the Gear Position Sensor prevent the shifter being moved to other gears while driving?
2) If the sensor is bad is the car still unable to be started when in Drive or Reverse?

Thanks
Barry

Post by **VCA** » 22 Feb 2010, 17:05

barrylay wrote:My 97 850 s/w can be shifted into reverse or park while the car is driving, but the car cannot be started (at a standstill) if I have the gear shifter in Drive or Reverse. Volvo has told me I need a new Gear Position Sensor. My Questions are:
1) Does the Gear Position Sensor prevent the shifter being moved to other gears while driving?
2) If the sensor is bad is the car still unable to be started when in Drive or Reverse?

Thanks
Barry

1.) No, it's just a sensor.
2.) Yes, that's part of the "Neutral Safety" function of the switch, the switch can fail in the opposite manner: car won't start even if it's in P or N.

barrylay · Post by **barrylay** » 22 Feb 2010, 17:31

So, if the sensor is not the problem, then what should I be looking at replacing to prevent being able to accidentally shift into Reverse or Park while driving? The Gear Shifter knob was kind of mangled, but when I replaced it nothing changed. There is a plastic stick that goes down the inside of the shaft from the shifter knob to the GP sensor, but it looks OK too. When I squeeze the release button on the Gear Shifter knob it doesn't seem to engage or dis-engage anything. I don't feel any kind of "click". It feels unconnected to whatever it was connected to.

Post by **VCA** » 22 Feb 2010, 20:17

barrylay wrote:So, if the sensor is not the problem, then what should I be looking at replacing to prevent being able to accidentally shift into Reverse or Park while driving? The Gear Shifter knob was kind of mangled, but when I replaced it nothing changed. There is a plastic stick that goes down the inside of the shaft from the shifter knob to the GP sensor, but it looks OK too. When I squeeze the release button on the Gear Shifter knob it doesn't seem to engage or dis-engage anything. I don't feel any kind of "click". It feels unconnected to whatever it was connected to.

Sounds like a broken detent in the gearshift assembly. Can you move it out of P without depressing the button? However, I don't believe there are any physical prohibitions on engaging R or P while in motion in the gearshift assembly of the 850...the TCM won't engage the R command unless vehicle speed is low enough, but if you throw it in P while moving, kiss goodbye to the parking pawl...that's mechanical.

barrylay · Post by **barrylay** » 23 Feb 2010, 12:56

Yes, I can move it out of Park without pressing the shifter button. I can move it anywhere I like without pressing the button. So, if the Parking pawl is gone, what's involved in repairing it? Sounds nasty.

Post by **VCA** » 23 Feb 2010, 13:04

barrylay wrote:Yes, I can move it out of Park without pressing the shifter button. I can move it anywhere I like without pressing the button. So, if the Parking pawl is gone, what's involved in repairing it? Sounds nasty.

Not the parking pawl (that's in the gearbox), the detent (which is in the passenger compartment). I've never repaired one, you might want to get a junkyard shifter assembly and swap the whole thing. Otherwise, hopefully this parts diagram will help you diagnose the problem...my guess is that you'll find part #24 broken.

barrylay · Post by **barrylay** » 23 Feb 2010, 13:54

Yes, I think you're right. Part #24 is actually totally missing because I can lift #23 right out of the shifter and there is nothing going through the slot where I see #24 is supposed to be. Maybe if I open up the passenger compartment housing I will find it there, or in the worst case, yes I can get a junkyard one from somewhere.

Thanks, I will post you about the result.

Barry

Post by **atomicpop** » 23 Feb 2010, 15:19

I just replaced the detent bar in my V70 this afternoon. Found mine was broken in two when I took the console cover off. ALso just discovered that while my microswitch is o.k. the mounting bracket/tabs that hold it in place are broken. No idea where/how to find a repalcement....

For the detent bar, Volvo part numbers you'll want are: 9181378 (detent bar) & 9181376 (rubber o-rings)

I bought replacement from TheVolvoSite (swedishautoparts.com):

http://www.swedishautoparts.com/shop/se ... art+Search

http://www.swedishautoparts.com/shop/se ... art+Search

Easy repair if that's all you need. Just remove the console and you'll be able to see where it slides through the gear selector mechanism.

Cheers!

barrylay · Post by **barrylay** » 23 Feb 2010, 15:55

Cool, thanks for the info.

Barry