brake warning light and stabiltrak light on

JerryIrons

Original poster
Member
Dec 20, 2011
434
This started happening on me. 2006 EXT. ABS light never comes on. Plus the rapid chiming you can get if you put the emergency brake on while driving. What's really fun is that just going down the road, the lights can kind of intermittently go on and off, along with the chiming :smile: I've even had it happen just parked in the driveway. I made a video of that maybe I'll post it.

Lots of times though the stabiltrak and brake warning indicator, once they come on, will stay on. I pulled the brake fluid level sensor harness, no effect. Jumped it with a paperclip, no effect. I measure the voltage through the harness and it's 1.5 volts, doesn't sound right but I don't know what the proper voltage is, or if it's pulsed etc. Brakes work perfect, and fluid level spot on.

No ABS codes, and no check engine lights. In fact I cleared everything, and just putting the car into run without starting will trigger the 2 indicator lights and rapid chiming.

I'm about the change the ignition switch to rule that out. Anybody else with any thoughts have at it thanks. I played around with the parking brake switch near the lever but it seems ok. On the rare times the lights go out, I can pull up on the parking brake and the brake indicator light comes on and off correctly, with a little chiming. Also the brake lights come on correctly when the brake pedal is depressed, I checked those as well.
 

Mooseman

Moderator
Dec 4, 2011
26,246
Ottawa, ON
Very strange that the ABS light never comes on. Usually, when there is a fault with ABS, it will light with the Stabilitrak light. I can't think of a situation where the BRAKE light would light with the Stab light.

I do remember from way back with my old S10 Blazer where the ABS light came on and just pulled the bulb for it. Well, the BRAKE light came on instead because of the bulb. Does your ABS light come on during the bulb test?

Are you able to read other body/chassis codes? With the Stab light on, it should give a code.
 

JerryIrons

Original poster
Member
Dec 20, 2011
434
I have autoenginuity so will fire that up again to try and read things, it's not as good as a tech 2 but much better than lots of things, I can activate stuff.

Changed the ignition switch and still same problems.
 

TollKeeper

Supporting Donor
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Dec 3, 2011
8,282
Brighton, CO
I am pretty sure it cant be checked with a standard scanner, it will require the uplevel scanner. One that can check ABS and SRS codes.
 

JerryIrons

Original poster
Member
Dec 20, 2011
434
I have an ABS scanner which can read things like bad wheel speed sensors. Plus my autoenginuity can do things like measure wheel speed, and activate the abs module, dump valves etc.

Here is a video link of me sitting in the driveway in park with engine running, about 45 seconds long. I rev the engine at one point to see if that affects it. This is the more erratic version, lots of times both lights are on steady. Yes there is a check engine light, but that has to do with P0017, which I have since cleared, along with ABS code clearing to make sure everything is clear. Same behavior put key to run, traction control blinks 6 times and brake light comes on. Start vehicle, same behavior and then usually both lights stay on.

 

JerryIrons

Original poster
Member
Dec 20, 2011
434
Does your ABS light come on during the bulb test?

Are you able to read other body/chassis codes? With the Stab light on, it should give a code.
I can talk to the instrument panel and do a bulb test, and yes the ABS light comes on during that test. Good idea though, I had not thought of that.
 

JerryIrons

Original poster
Member
Dec 20, 2011
434
Also it's not a case of turning off traction control. On the rare times things start acting normally, I can successfully turn traction control off and on, with the button on the side of the shifter, and the indicator light acts normal.

In looking at the brake warning schematic, the only thing that can turn that light on is the parking brake switch or the brake fluid level switch. Can you tell I'm thinking out loud now?

Are you guys able to talk to the EBCM module in your tech 2? (electronic brake control module)
 

JerryIrons

Original poster
Member
Dec 20, 2011
434
I think I got it fixed. Wondered where the EBCM module was, and saw that it's attached to the ABS valve under the car under the driver door. Saw that big connector and unseated it, kind of cleaned it out, and reseated it. Took it for a test drive and thought it was fixed at first, but then the same thing happened. Only not as much so I knew I was close. Drove home and this time unseated it, cleaned it out (although it really wasn't that dirty), put some silicon dielectric grease along the male end, and plugged it back up. Also decided to clean up that engine ground right there on the frame. Of course that bolt was so corroded I needed to get the hot wrench out and heat up both sides red hot. (I had replaced it years ago with a bolt and nut). Used the dremel wire brush to clean off the frame, and put a new bolt, nut and washers there. This was especially fun doing it in my driveway in 40 degree weather with rain coming down pretty heavily :smile:

That all being said, went for a test drive, gassed it up, half a dozen stop and starts and everything good. If it happens again, I might be dealing with a bad EBCM. Apparently those things like to have solder connections inside go bad but I am crossing my fingers so far so good. Thanks to those who replied with help, I really appreciate it.
 

Mooseman

Moderator
Dec 4, 2011
26,246
Ottawa, ON
After looking at the video, I was just gonna say that it's a ground or wiring issue.
 
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Dec 5, 2011
604
Central Pennsylvania
After looking at the video, I was just gonna say that it's a ground or wiring issue.
Probably this....

but dang if that doesn't remind me of the old ALDL and engine light blinking out codes in my Cutlass....
 

JerryIrons

Original poster
Member
Dec 20, 2011
434
Well this thing has reared it's ugly head again, same problem as before. I will check the ground connection but pretty sure that's not the problem. What I will do is just set up a jumper wire to a good ground and see if that makes all the beeping quiet down :smile:

The good news, I snagged one of those vxdiag connectors, that comes with tech2win software and it's working good for me. I may post a how to do that, it was a little tricky to install and configure but I'm talking to all the systems on the car now, and can finally update software on the modules and do an ABS bleed without having to drive it and slam on the brakes lol. Pulled a couple of C codes, one had to do with yaw sensor and another with torque but will start with the ground first. Last time I was able to wiggle the connector going into the ebcm to make things better.

Anyway, will post here tracking my progress.
 

JerryIrons

Original poster
Member
Dec 20, 2011
434
Put the vehicle in my garage, and set up a test ground wire running from the ground on the frame near the EBCM right to the negative battery post and no change. Wiggled the heck out of the connector and wires going into the ebcm, no change. After reseating the connector a few times, and tapping on the ebcm/pump lightly with a hammer to try and cause the solder joints to connect, I got the lights to go out, but that didn't even last a mile down the road before it came back on.

No trouble codes, not even any ABS codes. In fact, I can clear the codes, and then immediately after I get the same red brake indicator light comes on, along with traction control disabled. Went for a test drive tonight, and watched all 4 wheel speed sensors give accurate readings. I can talk to the EBCM via diagnostic software ok, but with autoenginuity I'm seeing negative voltage on the yaw sensor which is out of range. At some point I will fire up by tech2 clone and see what else I can find. The EBCM is definitely sending a signal to the main computer to illuminate the red brake light.

Service manual states that if the traction control light is always on, replace EBCM. (or fix the solder joints I guess)

I did snag a ebcm/abs pump from a junk yard. Started removing the ebcm from the junk yard pull, got the two top screws out ok, but bottom ones were so corroded I ended up grinding off the top of those screws and drilled a bit to pull the EBCM off. I still have to drill out the 2 bottom screws in the abs pump portion, they were completely corroded/galvanized in place. (once I got the EBCM off I tried using vice grips on the bolts that were sticking out but all that did was twist and break the bolt). My existing installed ebcm/pump screws are even more corroded than the junk yard pull. The abs pump bracket bolts are so rusty I will be extremely surprised if I don't break any of them if I elect to replace both ebcm/abs pump. So either way this is not going to be fun. But at least I will be able to use my favorite tool, the hot wrench :smile:

According to the service manual, there are only 4 ways for the red brake light indicator to come on:
1) parking brake engaged. (this works fine I tested it out)
2) low brake fluid or base brake pressure differential (up on the master cylinder, a difference in pressure between the front and back systems)
note a bad brake fluid switch can cause this, but I removed that switch and jumped it to test.
3) IPC bulb check
4) EBCM detects an ABS disabling malfunction which also disables dynamic rear proportioning.
Curious thing is my ABS works fine, I tested it out in the snow the other day, while both traction control lights and red brake light illuminated.

I think I will try putting the junk yard pull back together enough to test, and just plug in to my vehicle's connector without actually installing it, and see what happens. I'm leaning toward a bad EBCM, but really do not want to replace it and see the same problems happen, this is not going to be an easy job.
 
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wormwood1978

Member
Jan 3, 2015
93
Put the vehicle in my garage, and set up a test ground wire running from the ground on the frame near the EBCM right to the negative battery post and no change. Wiggled the heck out of the connector and wires going into the ebcm, no change. After reseating the connector a few times, and tapping on the ebcm/pump lightly with a hammer to try and cause the solder joints to connect, I got the lights to go out, but that didn't even last a mile down the road before it came back on.

No trouble codes, not even any ABS codes. In fact, I can clear the codes, and then immediately after I get the same red brake indicator light comes on, along with traction control disabled. Went for a test drive tonight, and watched all 4 wheel speed sensors give accurate readings. I can talk to the EBCM via diagnostic software ok, but with autoenginuity I'm seeing negative voltage on the yaw sensor which is out of range. At some point I will fire up by tech2 clone and see what else I can find. The EBCM is definitely sending a signal to the main computer to illuminate the red brake light.

Service manual states that if the traction control light is always on, replace EBCM. (or fix the solder joints I guess)

I did snag a ebcm/abs pump from a junk yard. Started removing the ebcm from the junk yard pull, got the two top screws out ok, but bottom ones were so corroded I ended up grinding off the top of those screws and drilled a bit to pull the EBCM off. I still have to drill out the 2 bottom screws in the abs pump portion, they were completely corroded/galvanized in place. (once I got the EBCM off I tried using vice grips on the bolts that were sticking out but all that did was twist and break the bolt). My existing installed ebcm/pump screws are even more corroded than the junk yard pull. The abs pump bracket bolts are so rusty I will be extremely surprised if I don't break any of them if I elect to replace both ebcm/abs pump. So either way this is not going to be fun. But at least I will be able to use my favorite tool, the hot wrench :smile:

According to the service manual, there are only 4 ways for the red brake light indicator to come on:
1) parking brake engaged. (this works fine I tested it out)
2) low brake fluid or base brake pressure differential (up on the master cylinder, a difference in pressure between the front and back systems)
note a bad brake fluid switch can cause this, but I removed that switch and jumped it to test.
3) IPC bulb check
4) EBCM detects an ABS disabling malfunction which also disables dynamic rear proportioning.
Curious thing is my ABS works fine, I tested it out in the snow the other day, while both traction control lights and red brake light illuminated.

I think I will try putting the junk yard pull back together enough to test, and just plug in to my vehicle's connector without actually installing it, and see what happens. I'm leaning toward a bad EBCM, but really do not want to replace it and see the same problems happen, this is not going to be an easy job.
I'm experiencing the brake light on and stabiltrak light on, no codes. Did you ever solve this?
 

TollKeeper

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Dec 3, 2011
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Brighton, CO
I'm experiencing the brake light on and stabiltrak light on, no codes. Did you ever solve this?
What kind of device are you using to get the codes?
 
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Mooseman

Moderator
Dec 4, 2011
26,246
Ottawa, ON
Cheap code readers won't pick up on EBCM or BCM codes. If you're getting an ABS and Stabilitrak light, it's a problem with the EBCM somewhere, maybe a wheel sensor, but you need to get the codes.

@TJBaker57 can help with getting set up with an Elm327 Bluetooth adapter and apps that can work to get those codes.
 
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wormwood1978

Member
Jan 3, 2015
93
Cheap code readers won't pick up on EBCM or BCM codes. If you're getting an ABS and Stabilitrak light, it's a problem with the EBCM somewhere, maybe a wheel sensor, but you need to get the codes.

@TJBaker57 can help with getting set up with an Elm327 Bluetooth adapter and apps that can work to get those codes.
Thank you for the response. I actually have a Autel good scanner along with a second older scanner that will do other extra stuff like ABS codes (not bi-directional though). Zero codes and I went through a lot of live data. With a little more internet searching, I found one cause could be low brake fluid. Yep, mine was down a bit, topped it off and no more lights. Next day or two, I gotta get it up in the air and see if I can find the leak. I'm doubtful it is worn pads, guessing its coming out somewhere. I'lll update this threat soon with the cause/fix.
 
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Mooseman

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Dec 4, 2011
26,246
Ottawa, ON
Never heard of low fluid causing ABS/Stab lights but it makes sense if it's not giving a code for that. You would think that it would have an actual error code for it but no, I guess they want people to just bring it in. In the old days, it would be the red Brake light that would come on for that, not the ABS.
 
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mrrsm

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The issue with such complex hardware -=will=- unfortunately come down to having a Bi-Directional Scan Tool that can actuate the sub-systems and sort of "Exercise" them while under Factory OEM Testing Regimens.

I can help you here with some of that... right up to the point where my Snap-On Modis Scan Tool encounters "Codes" and gives me a "Communication Error" because the vehicle needs to be hooked up to this Pro-Shop Quality Device and actually read them before designating which Tests it recommends be performed.

Nonetheless, giving you a "Bird's Eye View" by way of Screen Shots of what this kind of Scan Tool is capable of doing specific to your Year, Make, Model Vehicle should level your thinking and hopefully give you more Diagnostic Insights than any Generic Scan Information ordinarily provides. Here Goes Nothing:

The First 20 of the 47 Snap-On Modis Screen Images:
 

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mrrsm

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Second Batch of 20 of the 47 Total Screen Print Images:

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mrrsm

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Last Batch of the 47 Screen Prints:

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Mooseman

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Dec 4, 2011
26,246
Ottawa, ON
Re-reading this thread, a low fluid condition should light the red Brake light. Was that one also coming on? I could see the system disable the ABS/Stab if fluid is low in case there isn't enough to cycle the pump.
 
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TollKeeper

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As mentioned above, to read ABS, EBCM, or BCM codes, you will be required to have a bi-directional scanner. No other way around it.
 
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Mooseman

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Dec 4, 2011
26,246
Ottawa, ON
I don't think you actually need a bi-directional scanner, just one capable of reading the codes. Bi-directional is for when you need to send commands to modules, like actuate the ABS bleed cycle or move HVAC actuators. Even ELM327 Bluetooth adapters with an appropriate app can read all codes.

I any case, seems to be resolved for the lights as a low fluid condition.
 

mrrsm

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Be curious to see the Diagnostic Step-By-Steps for these issues covered for the "GYMKO" Tech 2. I'm guessing that the "Lil EBCM Hydraulic Computer" might need some "Poken' N Coaxin'..." Bi-Directional Wise ... in order to Test it out.

Standard Scan Tools might be great at showing the "The Effects" of the obscure problems involved... but seldom point directly at "The Causes"...and indicate what to do next...
 
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mrrsm

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Damn... I just Remembered... For Tech 2 Owners... THIS is a ready reference, "One Over The World" Tech 2 Bible that takes ALL of the 12 Tech 2 procedures and steps through each diagnostic...using an Alphabetized List to read and follow. Perhaps more Step By Steps will be revealed within:
 

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