How to change the steering shaft position sensor
Aug 7, 2010 14:02:53 GMT -6
bufo, Dominic, and 1 more like this
Post by Aurora40 on Aug 7, 2010 14:02:53 GMT -6
This is not documented well in the FSM. And they only document pulling the whole steering shaft out of the car.
My Aurora has had an intermittent "Serv Stability Sys" message popping up, which has gotten more regular. The system has never engaged accidentally, I've only had the message pop up.
There are only three sensors that are part of the stability system. The steering position sensor, a lateral g sensor, and a yaw rate sensor. Rather than pay $1-200 to a dealership so they can hook a Tech-II up, I chose to replace the cheapest sensor first. The steering shaft position sensor, which is about $60.
The easiest way to remove it is to partly remove the ISS. Start with your front wheels pointed straight ahead.
From the driver's footwell, remove the hush panel. There are two phillips head screws and a pushpin. Then as you remove the panel, carefully twist out the air temp sensor on the right side, and disconnect the lightbulb connector on the left side. The panel can now be removed from the car.
Around the steering column, you will see a black rubber sleeve, and a clearish rubber sleeve that runs into the firewall/floor. The black rubber sleeve needs to be removed to access things. If you did the ISS, it is probably already slit partway up. I slit it the rest of the way and removed it. You could try to just move it around, but I think that would be really difficult.
Now I secure the steering wheel. You absolutely do not want it to turn while the ISS is disconnected, or you will ruin the airbag clock spring. What I do is tape one of the steering wheel spokes around the wiper stalk. GM makes a pin-type tool also, but I don't have one.
The ISS has a bolt that holds it onto the steering shaft. A 13mm socket and ratchet is needed to remove the bolt. You don't need to put a backup wrench on the bolt, it has a tab welded to it that keeps it from rotating. Remove the bolt.
At this point, I take some string and feed it through the ISS bolt hole as I remove it from the steering shaft (not through the shaft and ISS, do it as the ISS is pulled out). The ISS can fall back into the car a bit, and this is just easier than fishing around for it. Either way, though, disconnect the ISS from the steering shaft.
You can now remove the steering shaft position sensor. There is a little blue plastic collar you have to remove (don't break it!), and then three little clips you have to push back, and the sensor can be slid down the shaft. Disconnect the wire harness, and slide the sensor off the shaft.
The new sensor will have a peg in it that keeps it from rotating. Keep this in there as you slide the new sensor onto the shaft. Try to have the sensor rotated so it is lined up more or less how it fits before you get it on the shaft. Because of the pin, it will not really rotate if you have to move it around. One you slide it up near the top, on the square part, you'll be able to rotate it a bit though.
At this point, you pretty much just reverse the process. Make sure to put the blue collar back on, as this locks the center of the sensor to the shaft.
I used duct tape to tape up the black rubber collar after sliding it back in place.
I took the car for a drive, and so far no Serv Stability message. But it was intermittent, so who knows. I did push it into some turns to activate the system, and it worked fine. If this doesn't fix it, the lateral g sensor is the next cheapest. The g and yaw sensors are simple to replace, as both reside in the trunk.
My Aurora has had an intermittent "Serv Stability Sys" message popping up, which has gotten more regular. The system has never engaged accidentally, I've only had the message pop up.
There are only three sensors that are part of the stability system. The steering position sensor, a lateral g sensor, and a yaw rate sensor. Rather than pay $1-200 to a dealership so they can hook a Tech-II up, I chose to replace the cheapest sensor first. The steering shaft position sensor, which is about $60.
The easiest way to remove it is to partly remove the ISS. Start with your front wheels pointed straight ahead.
From the driver's footwell, remove the hush panel. There are two phillips head screws and a pushpin. Then as you remove the panel, carefully twist out the air temp sensor on the right side, and disconnect the lightbulb connector on the left side. The panel can now be removed from the car.
Around the steering column, you will see a black rubber sleeve, and a clearish rubber sleeve that runs into the firewall/floor. The black rubber sleeve needs to be removed to access things. If you did the ISS, it is probably already slit partway up. I slit it the rest of the way and removed it. You could try to just move it around, but I think that would be really difficult.
Now I secure the steering wheel. You absolutely do not want it to turn while the ISS is disconnected, or you will ruin the airbag clock spring. What I do is tape one of the steering wheel spokes around the wiper stalk. GM makes a pin-type tool also, but I don't have one.
The ISS has a bolt that holds it onto the steering shaft. A 13mm socket and ratchet is needed to remove the bolt. You don't need to put a backup wrench on the bolt, it has a tab welded to it that keeps it from rotating. Remove the bolt.
At this point, I take some string and feed it through the ISS bolt hole as I remove it from the steering shaft (not through the shaft and ISS, do it as the ISS is pulled out). The ISS can fall back into the car a bit, and this is just easier than fishing around for it. Either way, though, disconnect the ISS from the steering shaft.
You can now remove the steering shaft position sensor. There is a little blue plastic collar you have to remove (don't break it!), and then three little clips you have to push back, and the sensor can be slid down the shaft. Disconnect the wire harness, and slide the sensor off the shaft.
The new sensor will have a peg in it that keeps it from rotating. Keep this in there as you slide the new sensor onto the shaft. Try to have the sensor rotated so it is lined up more or less how it fits before you get it on the shaft. Because of the pin, it will not really rotate if you have to move it around. One you slide it up near the top, on the square part, you'll be able to rotate it a bit though.
At this point, you pretty much just reverse the process. Make sure to put the blue collar back on, as this locks the center of the sensor to the shaft.
I used duct tape to tape up the black rubber collar after sliding it back in place.
I took the car for a drive, and so far no Serv Stability message. But it was intermittent, so who knows. I did push it into some turns to activate the system, and it worked fine. If this doesn't fix it, the lateral g sensor is the next cheapest. The g and yaw sensors are simple to replace, as both reside in the trunk.
