Lost Power Assist

[LandTug]

My 98 K2500 loses all power assist to both brakes and steering at once. This only happens ocasionally when coming off of freeway, foot on brakes and engine ideling. It does not die and will pick it up again as soon as I can get over my panic attempt to steer and stop. Blip the throttle and all is well again for who knows how long. Happens every month or so, just about the time I start to get comfortable with it again. Any ideas? Thanks.

[charliepeterson]

All assisting power comes from the power steering pump. The relief valve might be dumping.

[pjt97k2500]

I am experiencing a similar problem. After driving at highway speed and releasing the accelerator and allowing the vehicle to slow down, twice now in the last month I have had a loss of Power Steering and Power Brakes. I put the truck in neutral and hit the accelerator and the power comes back. I have a GM service manual and the diagnostics for this covers about 2 pages in the manual. A lot of the diagnostics is electronics which I do not have the proper equipment for. One thing that the manual talks about is the "Variable Assist Actuator" that is mounted on the back of the PS pump. Apparently the actuator reduces the power assist at higher speeds and provides more assist at low speeds and is electronically controlled through the VSSB. I am interested to know what the fix was in your case?

[patrick m.]

we replace many "steering wheel position sensors"
under dash mid way of column, common failure on 97ish tahoes, and subs as well.