Okay, so here's my "problem". I removed the traction control module from under my ABS unit, and re-plumbed the hydraulic output from it to the rear brake lines. My desire was to keep ABS and just eliminate the TCS "module" that's bolted to the front drivers side frame rail. After re-doing the rear brake lines around the TCS module, and removing it from the car, everything appears to be working great, except ...... I now have both a "Brake" light and "TCS Off" light on my instrument panel! Now if I re-plug in the electrical connector to the TCS module ..... all dash lights cancel.

So, here's my question: Can I install some kind of electrical "plug in", (similar to like O2 simulators), or bridge the electrical connector with resisters to make the TCS system "think" the module is still there and hooked up???? Anyone tried doing this before, that is, keeping ABS while eliminating the TCS "module"? Also, can these warning lights be "programed out" in the tune??? There are NO DTC/trouble codes set, just the warning lights are lit.

TIA for any replies!

 

The module on the frame rail is for the cruise control. Both the cruise control cable and the accel pedal cable connect to the TCS servo on the driver side valve cover. The servo is controlled by the EBTCM (ABS + TCS) module, As opposed to the EBCM (ABS only) module. Not sure how the EBTCM interplays with the cruise control, but I suspect it cancels/overrides the cruise control, uses the servo to control the throttle body.

That's my simplified view. I would suggest you download a free copy of the 1996 factory service manual, courtesy of GaryDoug. Should be 99% compatible with your 97:

https://www.mediafire.com/?40mfgeoe4ctti

 

Injuneer, first off Thanks! for your reply.

Fred, it seems like you're always the first to try and help out a fellow board member who's having some kind of trouble with their car, and that doesn't go unnoticed!

But, this time you are looking in the wrong direction on this. Maybe I've done a poor job of explaining this, but we are definitely NOT talking about the cruise control module here. As you well know TCS is usually activated in three (3) separate "stages" on these cars, depending, of course, on how severe an "intervention" is required. First off the ECM usually pulls spark timing to lessen engine torque/power. After that fails to mitigate wheel spin, that throttle servo motor attached to the throttle cable above the drivers side valve cover "springs" into action and attempts to reduce throttle opening, (as you did describe in your post). And finally, after "all else fails" the TCS module I'm asking/talking about .... actually applies hydraulic brake pressure to the rear two wheels to control/stop spin.

The TCS "module" I've removed is located directly beneath the ABS unit and is installed directly in the brake lines feeding the two (2) rear brakes, (on a four (4) wheel TCS vehicle).

If I knew how to add pictures to this post, I would send you photos of this "module", it's mounting bracket, and it's previous location on the drivers side lower front frame rail. Unlike the cruise control module, you do NOT have to remove any plastic panels to see it. Anytime you are under the car you can see it exposed, and bolted right near the drivers side sway bar bracket, (unlike where the cruise control module located).

Thanks also for the tip about Gary Doug's '96 service manual link. I'll check it out to see how this "module" is wired, and how I might be able to "fool" my car into thinking it's still there!

 

I actually know very little about TCS. Wasn't even available on my 94. When you mentioned frame rail, I pictured the cruise box on my car. Sorry if I misled you. They must have relocated the cruise box, because what you describe is exactly where my cruise module was. Was visible and I took it off when I deleted the front sway bar. But I don't have the plastic underbelly panel any more, because I have a fan assisted trans cooler in that location.

Again, sorry, old age must be taking control.

On the other hand I'm often the first to respond because there is no one else that seems to come here to help on a daily basis. I hate to see people’s requests for help go unanswered. In this case I guess it just went off the rails.

 

Injuneer, no need to apologize for anything! You have been a great help in assisting many people solve numerous problems with their '94-'97 LT1 F-Bodies ..... over the twenty (20) some years that I've been frequenting this board. And remember, GM made many changes between '94 and '97 on these cars. Remember when your '94 came with an un- vented splined drive Opti .... those were long gone by '97!

Fred, the obvious reason we don't get many replies here now, is probably because so many have moved on to LS1 powered vehicles. Seems like only "dinosaurs" like us .... still have (the "old") LT1 powered cars.

I'll keep checking back here to see if anyone else has "tackled" my current problem and is willing to share their solution, but, thanks (again) for all your thoughts on this!

(I've also got a post on the "Computer Tuning" board asking for help in tuning my newly built 396 stroker motor, but ..... that seems to have fallen on deaf ears too).

 

I looked at the factory service manual. The sketch showing the location of the ABS/TCS components neglects to show the location of the “TCS Hydraulic Modulator”. I believe that’s what you called the TCS Module. It appears from the cross-section drawings of the ABS Motor Pack and the TCS Hydraulic Modulator (TCSHM) that the modulator receives the output of the singular rear wheel ABS Motor Pack hydraulics , and splits it into separate modulated hydraulic outputs for the individual left rear and right rear hydraulic circuits. Appears to match what you deleted.

My first thought was simply swap out your EBTCM under the dash for an EBCM. Then reprogram the PCM with an ABS only program, and delete the TCS interfaces. But that would probably also require addition of the single rear wheel speed sensor on top of the diff housing, and adding the reluctor ring to the diff carrier.

 

Ding, ding, ding, we have a winner! Injuneer, you have redeemed yourself in spades.

“TCS Hydraulic Modulator”, yes sir that's GOT to be what GM calls it! My first thought however was, "if push comes to shove", I'll just lengthen the original GM wiring harness on the electrical connector to it, and ....... "bury" it someplace else in the car! No more brake lines are hooked up to it, so the only thing limiting where I can put it .... is the length of the stock wiring harness. And, as I posted before, when it's plugged in, all the instrument panel warning lights do cancel.

Now, on to that other "tantalizing" lead you've given me, where can I find that cross-section drawing of the “TCS Hydraulic Modulator”? Can you shoot me a link to it? Does it show anything about the electrical connections/components within the module?

I'm still hoping beyond hope (?) that just a couple of "bridging resisters" in the (now) open end of the connector .... can "fool" the PCM into thinking that the module is ...... still there!

 

The best thing to do is check the DTC list for the ABS+TCS setup and see what triggers the code, and what the system does in response. If it's something related to pressure, position of a piston, etc., it may set a code and disable the ABS.

The code descriptions show the related wiring diagrams, so you can tell which ones involve the modulator.

I think the ABS+TCS section of the manual is Book 1/Part 1, section 5E2. The cross-sections are right up front. They just show the hydraulic components.

 

And Thanks! (again) for this info.