Hey guys, my Uncle is trying to fix his daughter's truck, but I have never played with the late model stuff. Hoping someone here could answer his email to my Dad:

"Hi Doug, I'm trying to help Susan with her '98 GMC pickup. We have
determined from numerous reliable sources that the problem is the
steering position sensor. I can't find out with any certainty exactly
where this sensor is. All kinds of different answers on that one. Can
you or Scott through your greater experience getting info off the
internet help? No sensors are in or on the steering box or along the
column that I can see. That leaves the area of the center of the
steering wheel as a possibility but I'm not tearing that open just to
have a look. Oddly enough, there is what appears to be a pressure
switch in the back of the steer ing pump, it's function is unclear to me
but it wouldn't fit the definition of a "position" sensor. What do you
think? Tom"

Thanks guys, I figure you would be the ones to ask.

Scott

Can oyu tell us what the problem is that they are trying to troubleshoot. I have never dealt with a steering position sensor. Of course the newest vehicle I own is a 1995.

I've heard of this problem with a 99 Tahoe before...

Steering Wheel Position Sensor Removal & Replacement Procedure:

Set the front wheels in the straight-ahead position. Set the steering wheel in the LOCKED position.
Disconnect the negative battery cable.
Disable the supplemental inflatable restraint (SIR). Refer to Disabling the SIR System in SIR.
Remove the nut and the bolt from the upper to the lower steering shaft connection. Slide the lower shaft down.
Remove the position sensor connector by using a suitable tool in order to pull the connector down around the right side of the steering column for accessibility.
Important: Do not apply force to the sensor and the bearing in a sideways direction.
Remove the position sensor and bearing assembly from the steering column jacket by pulling the assembly straight out.
Remove the position sensor from the clips in the bearing assembly.

Installation Procedure
Install the position sensor into the bearing assembly.
Install the bearing into the steering column jacket.
Align the notches on the bearing and the column jacket.
Seat the bearing fulling into the jacket.
Connect the position sensor connector.
Install the bolt and the nut to the upper end of the shaft. Tighten
Tighten the nut to 62 N·m (46 lb ft).
Connect the negative battery cable.
Enable the SIR system. Refer to Enabling the SIR System in SIR.

what is the steering position sensor for??

what is the steering position sensor for?? For “Variable Effort Steering” aka variable assist steering.


Caution!!! Caution!!! Caution!!! Caution!!! If you disconnect the steering column do NOT turn the column while it is disconnected. The SIR coil needs to be maintained in its center point of travel. If you do not maintain this position the air bag may deploy at some point after it is reconnected.

I don’t think this is a job the average guy should attempt.

The “Variable Effort Steering” uses the pressure sensor in the back of the pump to increase the pressure when driving at low speeds( so you have easier steering) and to lower the pressure at high speeds( so the steering is firmer) . the position sensor must be on the steering column then, cause it is nowhere on the gear box.

the position sensor must be on the steering column then, cause it is nowhere on the gear box.
Yes – lower column

Another note of CAUTION:
There are technical service bulletins with revised procedures for replacing these sensors.

chevytech, is there a bypass for this system? Any way to defeat it and make steering effort same at all times? A change to larger tires wreaks hell on this system.

chevytech, is there a bypass for this system? Any way to defeat it and make steering effort same at all times? A change to larger tires wreaks hell on this system. If there is, I don’t know of it.

If it had full assist all the time it would feel like driving on ice, with no “feel” of the road.

I think the steering system should have been made so, when it has a failure it goes to a default mode, and performs like power steering did before Variable Effort Steering. The RWAL brake system did this seamlessly.

All the electronics, modules and interconnections between them are nice when these vehicles are new and working well, but as these trucks get old, the cost of repairing them is outrageous.

Personally, I would prefer to have less electronics, and I wish more of it were stand along systems independent of the major modules.

I am all with you on that!
That is what I was meaning with the steering assist, about a limp mode or somthing similar to regular old power steering. I talked with someone once that had the problem of it being waaay too easy, said it was like diving on jell-o.

chevytech, is there a bypass for this system? Any way to defeat it and make steering effort same at all times? A change to larger tires wreaks hell on this system.



what does big tires do to it? (i'm thinking about going to 35's at some point) and what size is "big."

From what ive heard there is a way to bypass the system. If you take the sensor out of the back of the pump there is supposedly a spring or something like that that you can take out, the sensor in the back is what raises and lowers the pressure. A mechanic told me about it, i guess they have problems with the sensor sticking and putting too much pressure too ften and it burns up the pump. good luck

Bigger tires obviously make low speed turning harder and it is usually even worse with the steering control system. By bigger tires, I am meaning anything with more contact area. On my 98 I have 285 75 on 16x8 0 offset rims and there is a noticeable difference at low speed( parking lots, etc.) in how hard it is to steer. It is not at all like having manual steering or anything, but is definately harder after the larger tires. I have also been told(not sure on the truth of this) that steering gear and pump with bite it much quicker on this system with larger tires. I know that larger tires or offsets will shorten the life of any steering system, but it is supposedly even worse with the gm steering speed/effort control or whatever it is called.