I need help please on abs- **SOLVED**

[Num12005]

Aight, i had this problem several months ago when it rained, now its back and even worse.
2005 tahoe, one day "service brake system" message came on and simultaneously the abs/brake lights illuminated, with warning chime and speedo goes haywire. It also wouldnt shift, i pulled over fir around 30 min and it made it home, i checked the grounds as recommended and it was fine, till yesterday. Its back and it will not shift out of 2nd, i replaced the speed sensor and looked over the abs module with no luck. Grounds are good, front speed sensors show signal when wheels turn, no chaffed wired, nothing i can see that is wrong. Any ideas?? Oh, and now the engine light came on after driving 50mi in 2nd!! Im lost, and very frustrated. Thanks for any advice

 

[PNWYukon]

Can you check for codes?

 

[Rocket Man]

Have you checked for codes? That's the first thing you need to do. If you can’t troubleshoot that way then it might be time to get a bidirectional scanner like a Tech2 so you can check the individual components like speed sensors etc. They can be had for $300-350 but it might take a week for shipping from China unless you can find an eBay seller with stock in the US.

 

[corvette744]

Maybe try autozone they will pull your code for free-if its a simple abs speed sensor code at least you will no which one it is.Maybe just replace it cheap around 20 bucks.

 

[Num12005]

Yea i currently dont have a way to pull the codes, i will have a snap on scanner loaned to me in a week or so but i need my truck now.
I changes the speed sensor and nope still does it. I changed both hubs 2 yrs ago, and i dont think the rear has speed sensors? I was just hoping some has had this issue cause i see alot on a google search but the fixes are all over the place..

 

[Num12005]

Maybe try autozone they will pull your code for free-if its a simple abs speed sensor code at least you will no which one it is.Maybe just replace it cheap around 20 bucks.

Yep, already replaced it and its the same.

 

[Rocket Man]

Yea i currently dont have a way to pull the codes, i will have a snap on scanner loaned to me in a week or so but i need my truck now.
I changes the speed sensor and nope still does it. I changed both hubs 2 yrs ago, and i dont think the rear has speed sensors? I was just hoping some has had this issue cause i see alot on a google search but the fixes are all over the place..

Yes the rear absolutely does have wheel speed sensors. What brand hubs did you use 2 years ago? If they’re not OEM or Timken one of the sensors in those might have gone bad in that time. Either get a cheap $20 code reader or go to any auto parts store and have them pull codes. Take a picture with your phone so you’ll remember what they are. It won’t tell you which one but it should point to the front or rear. That’s if this a speed sensor issue. There might be other codes. But if I sensor is bad it will cause these issues.

 

[Num12005]

I actually have a code reader but ny son has it 4 hrs away, lol. I used either the moog or timken i cant remember. The rain has something to do with it as i drove in heavy rain for 3 hrs the other day. It sat for 6 days then back home another 3hrs in heavy rain, after that its totally fubar!

 

[Num12005]

Im not seeing a rear abs sensor at all.

 

[exp500]

https://www.rockauto.com/en/moreinfo.php?pk=1416248&cc=1431156

 

[Rocket Man]

Im not seeing a rear abs sensor at all.

Where are you looking? Parts catalog or are you looking at your truck?

 

[Num12005]

https://www.rockauto.com/en/moreinfo.php?pk=1416248&cc=1431156

I read that some do not have a rear abs sensor, it said the speed sensor in tailshaft acts as one for the rear, but yea, i have my old rear end out of the truck and it doesnt have an abs sensor

 

[exp500]

Look for the VSS on tcase or trans. Losing Speedo and in limp home a bad indicator. I'm not sure what your truck has equipped wise. Some are internal. Know a transmission guy?

 

[exp500]

Found this in my files, describes your problem on earlier model.

 

[Num12005]

Where are you looking? Parts catalog or are you looking at your truck?

I have the old rear end out if the truck and definately no abs sensor..

 

[Num12005]

Look for the VSS on tcase or trans. Losing Speedo and in limp home a bad indicator. I'm not sure what your truck has equipped wise. Some are internal. Know a transmission guy?

Its just a 2wd 4l60e with "police pursuit " package.. 373 posi rear end.

 

[Rocket Man]

I have the old rear end out if the truck and definately no abs sensor..

There would be two, mounted with a 10mm bolt underneath each axle near the bearings with cables going to them. I thought all the NBS had them. My 02 Yukon Denali has them. If you had access to a Tech2 you could look to see what your truck used, probably the VSS in the trans like mentioned.

 

[Num12005]

I may send the abs module off and have it redone but i dont think that would cause the trans shift issue..idk, ive checked everything possible, except the codes. I really appreciat yalls help..

 

[Rocket Man]

I may send the abs module off and have it redone but i dont think that would cause the trans shift issue..idk, ive checked everything possible, except the codes. I really appreciat yalls help..

If the speed sensors have issues it can cause all kinds of trouble including going into limp mode where the trans won’t shift. I’m not sure if it does that for just ABS issues but the speed sensors will cause ABS issues so it’s all tied together.

 

[exp500]

Definately Scan It! Even if you take it to trans shop. Been guessing for a few days now. If you can't tell if you have rear ABS sensors, maybe its time to put it in capable hands before you destroy trans.