C5 Base steering assist wiring question
Thread Starter
Intermediate
Joined: Sep 2019
Posts: 35
Likes: 1
From: N.C.
C5 Base steering assist wiring question
Hi everyone,
I tried to search, but I think my ignorance on the proper terms defeated me. Or I had too many terms... anyhow.
There is an electrical wire that comes off the part of the steering rack that assists the driver (base of the steering shaft, has power steering fluid lines that go from it to the rack, determine which way to push fluid).
Is this just a 12v connector? Or does is it a VSS pulse input so it knows when to "dial back" it's effort when you get up to highway speeds? Or is it both?
If it does take a pulse input, can anyone tell me what the pulse frequency is per... MPH I assume?
Thank you!
I tried to search, but I think my ignorance on the proper terms defeated me. Or I had too many terms... anyhow.
There is an electrical wire that comes off the part of the steering rack that assists the driver (base of the steering shaft, has power steering fluid lines that go from it to the rack, determine which way to push fluid).
Is this just a 12v connector? Or does is it a VSS pulse input so it knows when to "dial back" it's effort when you get up to highway speeds? Or is it both?
If it does take a pulse input, can anyone tell me what the pulse frequency is per... MPH I assume?
Thank you!
Drifting
Joined: Mar 2015
Posts: 1,421
Likes: 302
From: CSRA, SC
The rack has an electronically controlled hydraulic assist that is powered by a variable DC supply. The EBTCM controls this supply to increase or decrease the assist based on your speed. It reduces assist at higher speeds and increases it as low speed. The frequency won't be varied, it will be the pulse width or % duty cycle. I don't have the specifics off the top of my head for the mapping and you may be hard pressed to find it. It may be in the dealer service manuals though.
Corrected: PCM does not control magnasteer coil current.
Corrected: PCM does not control magnasteer coil current.
Last edited by oharal; Sep 30, 2019 at 11:17 AM.
Drifting
Joined: Mar 2015
Posts: 1,421
Likes: 302
From: CSRA, SC
The way it works is the "off" or unplugged situation would cause you to be unassisted completely. The magnasteer can add or even negatively assist (making steering less assisted or harder than if you had unplugged it). This happens at 45mph if I remember correctly. So below 45 you get assist, at 45 its basically just a normal hydraulic rack, and above 45 its electronically negatively assisted effectively limiting hydraulics. I hope that makes sense.
Thread Starter
Intermediate
Joined: Sep 2019
Posts: 35
Likes: 1
From: N.C.
Yes that makes sense!
After your initial message, I realized Chevy (hopefully) wouldn't have designed it so if the magnasteer or the module failed, that it would interfere with the function of the hydraulics. Or worse, make it as difficult to steer as a manual steering rack (not too terrible at road speed, but a pain at stops/low speeds).
Thank you for the great information!
After your initial message, I realized Chevy (hopefully) wouldn't have designed it so if the magnasteer or the module failed, that it would interfere with the function of the hydraulics. Or worse, make it as difficult to steer as a manual steering rack (not too terrible at road speed, but a pain at stops/low speeds).
Thank you for the great information!
