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Hi all! Back again with the 96 eldorado. My traction control light came on and gave me a code tc0073. Started to come on and then would go off inbetween start ups when I would leave the last week or so. I tried resetting it using the on board diagnostics but as of 5 minutes ago it is still on. Any ideas would be greatly appreciated. Thanks

Edited by Mikemt68

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I pulled this from another place that had a bit of details on it. I could be wrong but I swear my 97 Deville has the same issue

bulletin regarding this particular trouble code - TC0073. Its

bulleting 63-50-16 dated May 1996.



Basically, the bulletin indicates that there was a software bug

in the EBTCM (Electronic Brake / Traction Control Module) for

1996 Cadillacs manufactured with the last 6 digits of the VIN

number that are smaller numbers than as follows:



Concours / Deville --- 280478

Eldorado ------------- 614516

Seville -------------- 826978



If you are not having a "real" problem and are getting an

invalid DTC due to the software bug you should be able to

duplicate the problem as follows:



First, turn the rear air conditioning blower to the lowest fan

speed setting. Then, reset the TCS codes to that TC0073 is no

longer shown. Now, turn off your engine. Restart the engine

after a few minutes and then run the diagnostics again. You

should find that the TC0073 does not show up. You should be

able to drive around, turn the engine on and off, etc. and the

TC0073 should not appear provided that you leave the rear air

blower set to the lowest setting. After trying this out, turn

the rear air to the highest blower setting and then turn off the

engine. When you restart the car and run diagnostics the TC0073

should reappear again as though you have a problem. If this is

what happens and your VIN number is within the range as

indicated above then you are getting an invalid TC0073 message. 

You do not need to do anything about the message. You could

replace the EBTCM since the new ones no longer have the software

bug but that would probably cost you well over $600 and it just

isn't necessary.

GM FAN FOREVER

Nice, clean, luxury= fine automobile

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@rockfangd, thank you! I tried to do that, got the code to clear but it came right back when I restarted the car, my Vin is smaller than the one shown. I have no issues except not having first gear with the traction control light on. Any other ideas?

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Remember it takes 3 cycles of the key to get the light to go out.

that is what mine does. 

I would suggest unplugging the plug from the EBTCM and cleaning the pins and terminals.

If that and the above test does not show anything positive and the code keeps returning you likely need the replace the EBTCM.

It is located underneath the air filter box on the driver side front.

It is mounted to the front of the subframe


GM FAN FOREVER

Nice, clean, luxury= fine automobile

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Are there any other codes? Specifically, any U codes? List ALL the codes, no matter how unrelated they seem.

The Electronic Brake Control Module (EBCM) and the Powertrain Control Module (PCM) simultaneously control the traction control. The EBCM sends a Requested Torque message via a pulse width modulated (PWM) signal to the PCM. The signal should be at 90 percent when traction control is not active and at lower values during traction control activations.


If the "DELIVERED TORQUE" input is lost the EBTCM will set DTC 73. The PCM monitors the serial data line to see if the traction control has been disabled by the EBTCM. If it has, the PCM will not set DTC P1571.
If the "REQUESTED TORQUE" input is lost, the PCM monitors the serial data line to See if the traction control has been disabled by the EBTCM. If not, the PCM sets DTC P1571 and communicates this to the EBTCM, via serial data. The EBTCM will then Set DTC 73.

DTC 73 may set if either the "REQUESTED TORQUE" or "DELIVERED TORQUE" circuits are shorted to ground, shorted to voltage or open.
DTC 73 may also be set if the ignition switch is improperly parked between "OFF" and "RUN," or if the Rear Console Blower Motor Control Slide Lever is left in the "ON" position prior to turning the ignition from "RUN" to "OFF." If either of these conditions set DTC 73 then replace the EBTCM.

Since this is a serial data line communication, I would disconnect both battery terminals and touch the disconnected cable ends together to clear all the modules. It may or may not correct the problem but what you should look for is a change in how the EBTCM reacts. If it goes back to the intermittent coming on and going off it would be a serial data line comm problem, which can get scary expensive to diagnose. If there is no change in how the traction light responds I would replace the EBTCM, mainly because it is one of the "BUG-INFECTED" ones.

The diagnostics for the '96 Eldo EBTCM required a pin-out box and the Tech1, so you are not going to be able to perform any meaningful circuit continuity or resistance checks without them. That pretty much limits diagnosis to visual wiring checks and connector faults such as loose pin contacts, broken or partially broken wiring  at pin connectors. 

CAUTION: DO NOT probe/puncture module wiring insulation with test light leads or DVOM leads.


THERE IS ALWAYS ENOUGH TIME TO DO THE JOB RIGHT - THERE IS NEVER ENOUGH TIME TO DO THE JOB AGAIN !!!

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PC1644 - Delivered torque output circuit - history.

When you get a chance do the battery disconnect I described above and let me know if anything reacts differently.

 


THERE IS ALWAYS ENOUGH TIME TO DO THE JOB RIGHT - THERE IS NEVER ENOUGH TIME TO DO THE JOB AGAIN !!!

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I'll do a little research on the circuits and see if anything jumps out at me tomorrow.


THERE IS ALWAYS ENOUGH TIME TO DO THE JOB RIGHT - THERE IS NEVER ENOUGH TIME TO DO THE JOB AGAIN !!!

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2009-06-10_230642_tc2.gif

Since you have the PC1644, I would physically check circuit 464 tan wire with a black tracer from the PCM to the EBTCM at PCM connector terminal #27 & EBTCM connector terminal #34.

Check it for continuity if you have a DVOM and make sure the terminal is not loose in the connector and it is clean, corrosion free. Use dielectric grease on that terminal when reconnecting the PCM & EBTCM.


THERE IS ALWAYS ENOUGH TIME TO DO THE JOB RIGHT - THERE IS NEVER ENOUGH TIME TO DO THE JOB AGAIN !!!

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Not without a memory refresher. I've slept since then.... Got Pics?

I'm thinking it snaps in place or there was one screw holding it in but I'm not positive...


THERE IS ALWAYS ENOUGH TIME TO DO THE JOB RIGHT - THERE IS NEVER ENOUGH TIME TO DO THE JOB AGAIN !!!

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5 torx bolts IIRC if you are talking about removing the EBTCM from the Valve assembly


GM FAN FOREVER

Nice, clean, luxury= fine automobile

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@rockfangd No there is a black plastoc cover over the EBTCM that I can't get off. It has one metal clip on it but I don't see or feel anything else and I can't get it off

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That is the PCM but you still need to get it out of the way. 

I was thinking the cover opened from passenger side to drivers side but it opens from front to back. Move the harness and you should be able to open the lid.


THERE IS ALWAYS ENOUGH TIME TO DO THE JOB RIGHT - THERE IS NEVER ENOUGH TIME TO DO THE JOB AGAIN !!!

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OK so that is the pcm, sorry new to these kind of repairs. So now I know it opens front to back, I tried every way but I did not move the harness it didn't look like it was getting caught on that but I will move it. Thanks for all of your help again. Is the EBTCM under the PCM?

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Just went out and checked the codes again and I have 2 new ones now: ip1552 history and pz1552 history. Those werent there 2 days ago so now I am wondering if I messed something up trying  to get that cover off I couldnt find much on Google about those.

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Those are both battery disconnect codes, disregard them.


THERE IS ALWAYS ENOUGH TIME TO DO THE JOB RIGHT - THERE IS NEVER ENOUGH TIME TO DO THE JOB AGAIN !!!

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