Abs Tcs no comm. stiff steering
Thread Starter
Intermediate
Joined: Dec 2014
Posts: 34
Likes: 1
Abs Tcs no comm. stiff steering
I have a 99 corvette and the abs tcs lights have been on for the past week. I've done pretty much everything to try to fix the issue including cleaning up the internals of my ignition switch which got rid of the problem for one day. I'm pretty sure the ebcm went bad but my main concern is the hard, stiff steering. When the abs fails the steering gets hard. My variable steering is stuck closed I guess. I even unplugged the rack and pinion connector hoping it would default to easy steering but it stays tough. Any ideas?
Racer
Joined: Nov 2008
Posts: 257
Likes: 0
From: Plano IL
I have a 99 corvette and the abs tcs lights have been on for the past week. I've done pretty much everything to try to fix the issue including cleaning up the internals of my ignition switch which got rid of the problem for one day. I'm pretty sure the ebcm went bad but my main concern is the hard, stiff steering. When the abs fails the steering gets hard. My variable steering is stuck closed I guess. I even unplugged the rack and pinion connector hoping it would default to easy steering but it stays tough. Any ideas?
Le Mans Master
Joined: Mar 2011
Posts: 6,835
Likes: 302
From: Columbia SC
My 2001 FSM does not have full details but it does show a variable 12 volt input to the Hi side. It also says that when the EBCM commands Magnasteer ON, it varies the current to control steering effort.
Based on the above it may not provide voltage when just sitting there and not at speed.
Here is a link to a discussion on design:
Of note is this:
In 1998, a second generation "Magnasteer " system was introduced on some GM vehicles. This version of the system does not use a permanent magnet, but uses a redesigned electromagnet that has one pole mounted on the input shaft and the other on the pinion shaft.
At low speed, there is no current flow through the electromagnetic coil. The level of steering assist depends solely on the calibration (stiffness) of the torsion bar. As speed increases, current flow to the coil is gradually increased up to a maximum of several amps to decrease assist and increase steering effort. Magnasteer uses vehicle speed as its only input, so there are no changes in steering effort during sudden steering maneuvers.
http://www.corvetteforums.com/forum/...question-1182/
Based on the above it may not provide voltage when just sitting there and not at speed.
Here is a link to a discussion on design:
Of note is this:
In 1998, a second generation "Magnasteer " system was introduced on some GM vehicles. This version of the system does not use a permanent magnet, but uses a redesigned electromagnet that has one pole mounted on the input shaft and the other on the pinion shaft.
At low speed, there is no current flow through the electromagnetic coil. The level of steering assist depends solely on the calibration (stiffness) of the torsion bar. As speed increases, current flow to the coil is gradually increased up to a maximum of several amps to decrease assist and increase steering effort. Magnasteer uses vehicle speed as its only input, so there are no changes in steering effort during sudden steering maneuvers.
http://www.corvetteforums.com/forum/...question-1182/
