Power Steering Failure

[CTOESHO]

I was taking a turn at 100+mph on a highway and I noticed for a sec that I lost power steering. *Note-no one was around, the road was clear, and I was just seeing how my tires gripped. Anyways, when I lost power steering for a second, I started to drift into the left lane. It caught me off guard and when the power steering kicked back in, The car pulled back into the right lane. What would cause this? Thanks.

 

[Mike Kopstain]

Vehicle Speed Sensor. I believe that 1993 is the first year of the variable power assist steering which gets firmer the faster you go and easier to turn the slower you go. The vehicle speed sensor is the most common cause for that problem. It usually won't throw a code unless it's REALLY out of whack, but check your codes anyhow. Let me know.

 

[naval-avi8or]

I get the same thing but not at 100 mph. Mine does it ever so often and it can be just backing out of the driveway or driving down the road. Mikey does it use the same speed sensors as the ABS if so that would make logical sense cause then it could determine that you were in a turn by sensing the difference between the to wheels.Anyway if you figure it out let us know.

 

[JonVH]

My '93 does it every so often in regular turns. I posted a similar question a while back but no one ever mentioned the VAS. What's a good way to determine if the speed sensor is the problem? & is it easy to fix/replace?
Cost?

 

[Mike Kopstain]

Well the easiest way to check is to pull the sensor and check it with a multimeter. I can get you guys the values from my service manual. Try running your codes first though. If it's bad enough it will through a code. When it was going out on mine I would be on an off ramp and the steering would get loose then tight then loose. In my case it was really bad. If the steering just cuts out for a second that signals that it's either a loose wire or the component is experiencing complete failure for a second.

I don't know if the VSS is used for the ABS. I don't believe it is, since each wheel has a gear on it for the ABS Sensor.

I'll get you guys those values later this afternoon.

 

[Mike Kopstain]

BTW: You ATX guys might also notice better shifting also. Typically another sign of VSS failure on an ATX is the torque converter either not locking up, or not unlocking until the car is slowed down to 10-15mph, which may feel like a thud.

 

[stevetatro]

I've heard it's recommended to replace the VSS on an ATX when you have the tranny removed (say, for a rebuild) because it's impossible impossible otherwise.

True? I don't know. If anyone knows how to replace the VSS with the tranny still in, please let me know!

Thanks.

 

[naval-avi8or]

Mikey please elaborate on this VSS position and if you know how to change it without taking the trenny out. I just had my tranny out and I don't think the shop replaced it.

 

[Mike Kopstain]

You definetly don't have to have the tranny out to do this. To find it just follow the speedometer cable down to the tranny housing and that's it. It is what the speedometer cable plugs into. The speedometer is held in by a pin that you just pull out.

Please note: The instructions that I am going to give you will give you an idea, but you do not have to remove the Y pipe. If you take off the intake it will be easier getting to it from the top. Also note that these instructions are for an AX4S, but all the ATX's have the VSS located in the same place. On the MTX-IV It's even easier, just look at your thermostat housing. The VSS is 6" closer to the firewall and down.

Vehicle Speed Sensor (VSS)

AX4S Trans axle

Removal

Raise vehicle on a hoist. Refer to Section 00-02.

Remove Y-pipe and heated oxygen sensors (HO2S)(9F472) from the exhaust system.

Remove VSS exhaust heat shield.

Remove bolt retaining VSS mounting clip to transaxle.

Remove VSS and driven gear from transaxle.

Disconnect electrical connector and speedometer cable from VSS. NOTE: Do not attempt to remove spring retaining clip from driven gear with speedometer cable in VSS.

Remove driven gear retainer and driven gear from VSS. Installation
Position driven gear to VSS.
Install gear retainer.

Connect electrical connector to VSS.

Ensure internal 0-ring is seated properly in VSS housing. Snap speedometer cable into VSS housing.

Install VSS into transaxle and secure with retaining bolt.

Install VSS exhaust heat shield.

Install Y-pipe and heated oxygen sensors to exhaust system.

Lower vehicle and verify proper speedometer I odometer operation.

Let me know if you guys need any more info.