Flashing ABS and TCS light

[Dans 01]

The other day when first starting my car the ABS and TCS light were alternately blinking very rapidly. I did some basic research on this, which would suggest hub, wiring or EBCM. The next day the ABS light went out while driving only to come back on a few minutes later flashing rapidly then stayed on solid. I would suspect this would be indicative of the wiring that leads to the sensor. I don’t know which side since I do not posses a Tech II. Anyways I was about to inspect the wiring on both front sides when the ABS light now has been staying off more than on. At the moment ABS light is not illuminated at all. It is freezing outside and now that it seems to have fixed itself temporarily I am more than likely just going to wait until the problem pops up again or wait until it gets warmer outside and then inspect the sensor wiring very closely such as where it bends up from the control arm. Don’t fix it if it ain’t broke ‘eh?

My question, does anyone know if there a difference between a flashing or solid ABS light in our cars and what does either indicate besides there is a problem with the system?

[Scottydoggs]

good chance the plug to the hubs are dirty if all you did was maybe pull on the wire or push it while inspecting it.

cleaning the plugs may help.

you can also check the hub for play by jacking the wheels up one by one, (you have 4 wheel abs) leave the lugs tight, and push and pull the top of the wheel firmly feeling for play.

[Dans 01]

Have not touched or inspected a thing yet after it presently seemed to fix itself. Could be dirty plugs too as the roads around here are near white from the city over-salting even though it has barely snowed at all. I see cars driving trailing dust clouds of salt behind them. Pretty sure the whole under body of my car is coated with that conductive crap

[Scottydoggs]

check the hubs like i said, bad hubs can set the abs light off and on as they see fit, wires bounce around some or get torn up over time.

[Dans 01]

Appreciate the tip on the hubs, I did rotate tires a few months back and the hubs checked out fine. I know I'll have to recheck them as something could have happened between then and now but due to weather I'm not eager to do so atm. I'll post what the trouble was once I get it sorted.

[Scottydoggs]

if you dont find bad wires or a bad hub, have it scanned, or you'll be throwing money at parts not knowing if it will fix it.

abs scan will need a shop to do it and most will charge you to do it. but its worth it in the long run.

[Kolton Lock]

I've had success with the scanners at like OReilly Auto. They read ABS and you pay a deposit to rent and you bring it back and get your deposit lol

Thing is with these cars, hubs will just start tripping out for no reason. They can make the engine bulletproof, but between Window motors and wheel hubs... I just don't know

[SlowNA06]

Kolton: Let us know the specific model of scanner you used. To my knowledge, there's only one outside of TechII's (and maybe Snap-On?) that'll work for most of our model years... sseilmnop posted about it I think. Like $100 on amazon if memory serves. EDIT: OTC 9450



There are some shops out there that will scan with a TechII for free (I use one) - check around. Otherwise, find someone to do it for cheapest.

One of the issues here is that the car has a faulty EBCM from the factory - they all eventually (might take 80,000 miles, might take 500,000 miles) have a problem and require a rebuild.

A scan will tell you either:
1) It is most definitely the EBCM; replace it and you're good.
or
2) It's most definitely NOT the EBCM; It's xyz hub... or a dirty connector... or the wiring has a short. Look for continuity, clean the connector, and then try a new hub if the problem persists.

All told, this issue should cost you less than $200.

[theclarks1]

mine was caused by a bad hub bearing after the struts were replaced. i had been hearing a noise, guess it just happens.

[Kolton Lock]

Whoops I just noticed... I meant that I've heard of success with them.

I haven't used one personally, although I need to lol cause both my lights are on

[Dans 01]

UPDATE:

Decided to get off my lazy arse and attempt a resolution here as the problem did come back a week after my initial post. The ABS light came back on, then to go out a few times while driving, only to come back on shortly thereafter. Lately it has been on solid every time the car is started and the entire driving cycle.

I did try the local O’Reileys, thus they did not have the proper scan device. I do have a DMM and know how to use it so decided to just dig in. Being that it is mentioned the hubs/wiring are likely culprits I tested both front wheels for faults. Both fronts test just shy of 1200 ohms all the way to the EBCM connector. I also found one front hub has some play and will need eventual replacement although is not creating the ABS issue.

I happened upon a thread today with the most excellent information on this very subject. http://www.grandprixforums.net/abs-stays-73037.html in Post #3.

After seeing that it is looking like the problem is most likely the EBCM itself. My car turns on the light upon startup before I get moving every time. However I am not eager to shotgun replace it unless absolutely sure. Shotgun troubleshooting I don’t mind as it costs me nothing and has so far given me a greater understanding of the entire system and how to make a quicker repair if faced with the same problem next time around.

Question: Does any one here have the wiring diagram for the EBCM terminal block connector itself? Probably a longshot but there is a lot of wiring at that connector and I like to test whatever I can there. I’d hate to just replace the EBCM to later find out there was some other wiring issue leading to it possibly creating the fault.

@SLOWNA06, Appreciate the tip on the OTC 9450. I wish I could buy that but pinching pennies is a must at the moment. Scan tool would be a nice thing to have handy and I should already own one by now but don’t. Once again thank you for taking the time to post that.

[Scottydoggs]

the abs has its own computer, so yes it sets the light, its telling you that theres a bad connection, aka its not communicating. or the ebcm is bad or hub. only scanning can lead you in the right direction. unless you find a bad wire or plug.

you will need to go to a good garage, or a auto body shop. yes, they will charge you. they are using a 3 or 4 thousand dollar scanner, that costs another thousand a year to keep updated.

[johannib]

If you suspect the EBCM there is a few places that rebuilds them. It is my understanding that there are little jumper wires that are soldered in and they have a problem breaking due to cars vibration etc... Also believe they replace a few know problem components. You can send in your module and they will test, repair better than new, and also retest and clear all codes from computer. You can acutally take your computer off and send in and still continue to drive your car as this only disables ABS, which if you have codes, it's already disabled. Cost for a Bosch 5.4 rebuild $160. A new computer from dealer will cost you around $700 or so. Here is a link if you are interested. They also have an ABS wizard tool thats asks you questions to help diagnose your problem. Good luck

ModuleMaster

[Dans 01]

Hi Johannib,

Appreciate you chiming in here. Yes I do suspect the EBTCM based on your advice in the other thread and how you described the EBCM/EBTCM verification tests upon startup and while in motion. That could only have been written by someone who has a great understanding of system function.

Not original the owner but as far as I know the EBTCM appears original to the car and has lasted over 100k miles. The black duct tape over the connector was untouched until I released the cam lock yesterday. Once I did that the tape pretty much crumbled and turned to dust with exception of the reinforcement strands.

The jumper wire phenomenon you mention is quite interesting! You are quite the wealth of knowledge on this I must say. I have noticed the ABS light a couple of times previously turn off after hitting a bump in the road, so the vibration issue could very be the culprit. Based on that I am going to see if I can repair it myself by retouching the solder pads if possible. Worst case and no resolve I can send out for repair and I’m only out some time to which I don’t mind. Sounds a lot like the Heads Up Display issue where the display goes dim and the fix is a touch up on the photocell pads. Performed that repair a while back and no issues with the HUD ever since.

I did find info on MM last night while searching the net. Thanks for posting that in case I hadn’t looked. The only concern I have with MM is that if I recall correctly is they state they do not test every unit once repaired. Not sure if it is due to fixing every problem area known to exist, or they’d have to stock a multitude of various make and model year vehicles to test them, making that unfeasible. Just a guess there, however their fee is much more appealing than the alternative

I’ll report back in a few days with whatever outcome arises. Thanks again for the wonderful advice.

[johannib]

Dans 01,

I would ohm out your wheel speed sensors first just to make sure, before you unseal your EBTCM, there is only 2 wires and you should read between 600 and 2400 ohms. Here is a video of a Bosch 5.3 not sure which EBTCM model you have. VW Audi Bosch motronic 5.3 ABS repairing - YouTube

So there was a change from 5.3 to 5.4 so they may not have the small wires that are being resoldered here. And your right about MM not retesting certain EBTCM's after they are done with their fixes, however if you get your reworked EBTCM and it doesn't work you can return it and they will send you a known good one I believe.

I have the same issue with my car so I need to replace/repair my EBTCM also. I did price one at the junk yard here in Iowa and they wanted $170 for the whole assembly, which includes the ABS modulating pump along with the EBTCM. Said if it doesnt work to return it for full refund. May be a route to go if you haven't checked into it.

Good luck, let us know what you come up with.

[Dans 01]

As per the diagrams someone was gracious enough to let me view I took a little time to see what I could possibly check for. Not much more to test for other than power, ground, brake signal, and all four speed sensor signals could be verified. It was however a good exercise for me to gain a greater understanding of the related system components and how they are connected together. Don’t mind doing this but I wouldn’t want to repeat this exercise. A month ago I knew nothing about ABS systems and almost feared having ever having to work on one.

More to follow once I have further news to report.

(edited for clarity)

[Dans 01]

Johannib,

Just now seeing your latest post. MM's wizard said I have the 5.4 module. I'll check that video too just as reference, never would have thought of that being on YT. Thanks!

[Dans 01]

Had a scan done at a local shop with a $6k Snapon brick and only codes to be found are P1571 and C0244

Codes were cleared and I drove it home. No ABS or TCS light on, although I figured it would just come back.

Next day upon initial startup the ABS and TCS lights illuminated and stayed on before I shifted out of park.
Next startup after that same thing, although the ABS light went solid, then flickered, then solid.

Further research on my own indicates possibly the EBCM, a wiring issue, or even the PCM (<wonderful).

Looking around the net I see another person with the same issue, however they had a C0550 (internal EBCM error) to which I do not. If that was the case EBCM would be in a box on it’s way to MM.

At this point I think I am going to invest in a scan tool such as the OTC earlier posted to avoid keep paying for the scan multiple times over.

Also trying to look for a PC based FSM specific to my car but no luck thus far finding one.

[SlowNA06]

P1571: Can't find that in the GM manual for some reason. Short on time so I didn't read it, but this came up: GearChatter.com :: View topic - DTC P1571 Traction Control Torque Request Circuit

C0244: EBCM most likely needs a rebuild (think that's the code I ran into) - they're faulty from factory and most eventually break from poor voltage regulation or something. It's like $150. You might be able to test voltages off the harness with a multimeter if you can find a wiring diagram. Personally, I'd shotgun the rebuild, then shotgun a PCM if necessary. No harm in buying the scanner, though.

[theclarks1]

Ok, so ive been through most of mine, and from what I can tell this started when the struts were changed. It had no issues before with the lights. So I dont know where to go from here, the lights light up before I even start the car and no matter if ive cleared the lights by removing the battery cable and letting it sit for a while or take it back to the garage and let them clear it, still comes back. So the last time, they replaced a bearing on the rear, after they had tested them with a multimeter, I tested both of the front bearings and they were fine, I moved the wires, traced a few of them on the front and still get the ohm's and 5v at both of the sensors coming from the harness. My question is, should I go the module route at this point? would an alignment issue cause this? I have the ABS, traction control, and variable steering light on.