99 Yukon EBCM Question? Help!

[CarolinaYukon]

Hey All,

Newbie here and say great site. Just 1 question before pulling trigger on remfg ECBM. Bought my truck 2 wks ago with ABS codes. Swapped Speed sensors and new brakes all way around. Took out for ride today codes gone!

Now, when slowing to stop about 8-5mph, the pedal shimmies and can hear abs pump turn on, but only for second or two and then stops. Not continuous. So, does this sound like ECBM to everyone? No codes and no other issues with braking system? Found guy on ebay who is in MI and rebuilds them with lifetime warranty and has about 10K feedback with 100% positive rating and wondered if anyone has used him if everyone feels the ECBM is the culprit.

Also, I know ECBM located under drivers seat in frame rail and do feel a bit of small vibration under my left foot when this happens. So I am inclined to believe ECBM but wanted everyone's feedback since this is my first chevy suv.

Thanks!

 

[SunlitComet]

So you replaced the front wheel sensors? Because it sounds like you are still ahving issues with them. And your ABS unit is under the hood mounted on the left fender well and not on the frame rail. Based on the vehicle description you gave that is.

 

[83 Bimmer]

If you have already replaced both front speed sensors I would suggest pulling the wheel speed sensors back out and seeing if you can take a peak inside the hole, it might be hard to see though. What you are looking for is a lot of rust buildup or debris inside the hole where the tone ring is.

Sounds like your abs unit might be getting a false signal from the sensor thinking one of the wheels is not spinning. If the tone ring is all clogged up with rust it can give the same signal as if the wheel is locked up.

If there is a lot of buildup in there you might have to replace one or both of your hub assemblies. It does not sound like the unit is faulty to me though, that vibration you feel is most likely just the abs pump activating.

Also if you have the capability of reading live data from the abs unit you might be able to see which wheel is giving the bad signal when the abs pump activation is actually happening, might need someone to drive while you watch the scanner though

 

[SunlitComet]

On the obs I don't think there is live data avaible for abs. The systems were not even on the same communication system as the pcm. I think it is code retrieval and solenoid activation for function testing and bleeding only. And for the rear there will only be one sensor either on the tranny tail housing or the t-case if 4x4. Sounds awfully a lot like the TSB about low speed activation because of the front sensors. Perhaps the reluctor rings are degraded somehow.

 

[CarolinaYukon]

Hey all

Sorry, meant to say the ecbm is in the engine bay. Was reading a post about one in the frame rail before. Yes, replaced both sensors with new ones. Cleaned both holes the sensors in and no real rust to speak of. R front bearing smelled ok and had clear to yellow grease while left front (timkin sensor) smelled like motor oil and was a darker color grease? Have a brake scanner and can see real time and can have the mrs. drive tomorrow?

So, I guess it may be a bad hub? Wife's 04 Pontiac had same issue and when I replaced hub it was fixed. Any thought or way to diagnose? Had 6 codes before replacing sensors and now none.

Here are the old codes from the scanner : c0226, c0222, c0237, c0282, c0223, c0221. Any thoughts? Like I said no lights now when truck on. What is the rear speed sensor? Saw that code in there?

---------- Post added at 11:10 PM ---------- Previous post was at 11:08 PM ----------

Disregard rear sensor question.. Just saw the last post. And truck is 4wd. Thx!

 

[CarolinaYukon]

So I wonder if its the Ecbm or bearing/hub since no codes anymore. But the old codes listed for all 3 of the sensors said each sensor was bad and reading erratic. Any thoughts on what may cause all three sensors to throw codes at once? And is the ecbm in control of that or does it react off the codes?

FYI, all brakes were shot and should have been replace by prior owner some time ago, if that makes any difference.

 

[SunlitComet]

Everything for the most port terminates in the EBCM. it shares the speed sensor data with the pcm and cruise and what not and it does all proccessing in that module which is sepre\artble form the hydraulic portion. To have that many codes floating I would diconnect all the connectors and inspect for damaged terminals. The rear sensor monitors the rear driveshaft it self instead of individual rear wheels. It is located where I mentioned on my previous post. I must know, what exactly are you using for accessing the brake module? Make and model of the scanner please?

 

[CarolinaYukon]

I have the actron scanner CP9449. But like I said, no codes at all now. Did change the sensor in the transfer case last night to be sure it was not problem and no change. Did want to know if there was supposed to be any small shims or washer in the shape of the wheel speed sensor and hub itself. With all the talk about spacing I looked at my setup last night and saw the passenger side hub has a small spacer/washer and was made to be there from some company but my new units didn't come with any. Wonder if this would be enough to cause issue?

Guess if i take out the little spacer and same issue it's eithe ecbm or hubs, ugh. This is such a PITA!! just don't want to throw money at parts if not the problem. Thanks for all the help!

 

[SunlitComet]

No spacers that I am aware of in thr parts list. However they may just need to be reused to acheive the proper gap.

 

[CarolinaYukon]

Went ahead and removed the small spacer (looked like a soda can tab) and the checked the front drivers side sensor mounting area. Driver side mounting area ha some rust so I cleaned and put small amount of spray paint and put all back together. Viola!! No more abs shimmy in low speed braking. Don't know if spacer or rust but either way problem fixed. Thanks again for all the help!!!