Excellent Glad I found this! Must read!

Thanks Sahlbon for the excellent write up. Followed and code:tiphat C0226 and brake problem went away. I did measure both sides sensor output so I had a baseline to work with. The rust on the left side had rusted the pin holding the stainless strip and it was lifting up from the rust. Must read!

 

Do you think the weather has something to do with condition

I was experiencing this same condition in the winter as soon as weather got warmer the abs kicking in at low speeds for no apparent condition went away.
I have changed both front sensors but condition still occurred?

 

ABS code C0265 and C0226

Check the readings from both sensors, see if they match. All you need is a cheap multimeter. Ohms and AC milivolts

 

simple fix

Got to agree with everything said. I had the abs problem also, at low speeds, been going on for awhile now, then finally, my hub gave out. I just changed out my hub, and in the process saw all this rust your talking about on the old one. Just for the heck of it, I cleaned up the area around the sensor, popped the rivet, and wouldn't you know it, RUST. I only have 83000 miles on my tb, its a 2004. Hope I don't keep having hub problems. The right side was changed out with only 40,000 miles, at a repair shop. This time I did it and used a Timken.

 

abs wheel sensors 02 trailblazer

hey everyone I'm new to this i just got an 02 trailblazer LT 6 months ago it has 106k on it n the shop is saying my abs wheel sensors r failing my question to everyone is where exactly are the abs wheel sensors located n also is it a hard diy project i have the tools i have the garage but i don't have the exp.in abs wheel sensors please help my truck is my baby must fix u can email me at xxaray08081xx@icloud.com or u can post your thoughts on here thanks in advance

 

Aray63

Dude,

You shop would have to give you more information than your sensors are failing! Are you having any problems with braking? Did your ABS lite come on? Then you would need to know which one? Codes would be the key to helping to resolve your issue! ABS can be read out on the more expensive scanners, find one and you may be able to help yourself. there is a lot of information on this website.

 

The abs sensors are located in the wheel hubs for the front wheels and the same for the rear except they are separate from the rear wheel bearings. As for the abs feeling funny at slow speeds, and especially when coming to a slow stop, I found what i think is the cause. I had a front left wheel hub going bad over a really long period of time, about a year. It didn't act like i thought a bad hub would act, it made a humming noise inside the car that just kept getting louder as time went on. Not the usual clicking noise you would expect from a wheel hub. The only way i figured out it was the front left was by driving, making wide left and right turns. Anytime i made a left turn the humming would go away, completely, but on the right turn the humming stayed constant or got slightly louder. Now for the hub i removed. holding it in my hand and turning the hub, for about 180 degrees it was really quiet and smooth, but for the other 180 degrees it bound up and was hard to turn. This is what i think was throwing off the abs at slow speeds and when stopping, each time it would hit the half that was binding the abs sensor that is built into the bearing thought the wheel was sliding and thus kicked in the abs. The sensors are extremely sensitive, they would surely pick this up. Anyway, after changing the faulted hub the problem went away and has been good now for over 9 months. As for difficulty, changing the hub is really simple. The hardest part is getting that darn center nut off. It was a 36mm. I think there's a video on youtube, and this site showing how to do it. Another thing, i would be very careful to get a good quality replacement hub, not some cheapest on the market. It's just too important a part to take a chance with. I bought mine off amazon, a timken part, i believe it was $140.00. You can find them out ther for 40 bucks, but i don't think the quality is too good. hope all this helps.

 

abs wheel sensors

okay ill get the codes n post them if it will help i know it was mis firing in cylinder 3 n it was kinda lk putting around so i took it to my buddies shop n no abs light juss service engine soon but i know thats from it missing but the night b4 it started to act up tge service 4x4 kind of blinked on n off a few times n went off no abs light but my buddy said abs sensors both sides n its miss firing so wen i go up there ill grab the code sheet n post thanks to everyone look forward to ur thoughts after i post codes

 

Thanks!

For posting this thread. We've been suffering with this issue for months. Finally got it fixed using your guide.

For those just coming upon this I'd like to add that once you take the hex screw out the sensor may stick in the hole. Gently pull it straight out. Be careful not to pulll on it hard because it may suddenly pop out and you might rip the wires out of the sensor. Yup, that's what happened to me .
Luckily I'm handy with a knife and soldering iron and I was able to shave the housing down, re attach the wires, and seal it up with silicone.:woohoo:

Also, I used a file to clean up the surface of the hub. It was amazing how much rust there was under the shim. Great design!

 

ABS Problems - Wheel Bearing Hub Assy. WIth Sensor

As stated in a prior post, worn wheel bearings can cause the ABS sensor to activate the abs system at inappropriate times.
.
Having owned three Trailblazers, I have found the bearing assy. needs to be replaced between 150,000 - 185,000 miles in my experiences.
.
That said, a wheel bearing hub assembly WITH ABS sensor can be bought online for $65 WITH shipping cost included.
.
Normally I would be afraid of such a low cost. However, I have bought such low cost assemblies previously and have driven with no further problems.
.
One low cost bearing supplier can be found at 1AAuto.com.
.
While I don't advocate random or haphazard parts replacement, I don't recommend spending $200 worth of time in testing to avoid a $65 expense.

 

that may be true.

I haven't changed a bearing or Hub on the trailblazer yet, but my experience with my audi taught me that you can't change one with out the other.

If u want to change the hub, you're going to damage the bearing taking the hub out and therefor would need a new hub and bearing...

is that how it is with these?

And yes, a hub/bearing assy could only cost $65, but don't you need a bearing press as well? with can cost a pretty penny to rent/buy...

 

Simple Fix....

The hub/bearing assembly is a single unit and is not separable. After removing three bolts that hold the assembly to the yoke and a large nut on the spindle, it is removed by use of a gear puller. Re-installation does NOT involve a press as the hub is simply pushed onto the spindle by hand and bolted in place.

I suggest buying a Chilton's Repair Manual at your local auto parts store for the correct year of Trailblazer. They cost approximately $15 - $20 in many areas and are money well spent as there are many other repairs for which you will need a manual including torque specs.

 

how do anyone even know that it is only the front assembly that needs replacing?

Would there not be at least one sensor on the rear as well?


and again, please excuse my ignorance, I've only changed bearings/hubs on an audi before...and a bearing press was need push the hub out, and the bearings, and to press them both back in...

 

Simple Fix...

There is no bearing hub assembly on the rear axle as the race and bearing are on the axle and in the axle housing. As replacing rear bearings is truly a major undertaking and not normally associated with abs problems, that is not even a consideration.

However, the rear does have an abs sensor which is not normally associated with abs problems caused by bearing wear. One problem mentioned by others is corrosion causing interference with electrical connectivity which may be more prevalent in areas where highways are salted due to icy conditions.

That said, the most likely source is at the front hubs where I suggest you start by process of elimination.

And again I suggest a $20 Chilton's Manual from your local auto parts supplier which will save you time and avoid further delay and far greater expense in the event of a vehicle breakdown at the time and place of the vehicle's choosing.

 

Rear wheel ABS sensors

Hi, I was testing the front sensors and they are OK, but when I tried to find the rear sensors I could not locate any wiring from the rear wheels for them. Can you educate me on their location and wiring route?
I know there is a problem in the rear because I tested the ABS by braking hard in a wet parking lot and the rear tires locked up. The fronts did not.
Thanks,
Philip

There is no bearing hub assembly on the rear axle as the race and bearing are on the axle and in the axle housing. As replacing rear bearings is truly a major undertaking and not normally associated with abs problems, that is not even a consideration.

However, the rear does have an abs sensor which is not normally associated with abs problems caused by bearing wear. One problem mentioned by others is corrosion causing interference with electrical connectivity which may be more prevalent in areas where highways are salted due to icy conditions.

That said, the most likely source is at the front hubs where I suggest you start by process of elimination.

And again I suggest a $20 Chilton's Manual from your local auto parts supplier which will save you time and avoid further delay and far greater expense in the event of a vehicle breakdown at the time and place of the vehicle's choosing.

 

hey guys,

WHERE CAN I BUY SHIMS??

im having this issue on my silverado and my familys tahoe.... cleaned up the hub etc, but the new sensors i bought stick in .73" when the old ones stuck in .67"

if i were to install these and run the truck, the reluctor would catch the sensor and break it... if i had shims id be all set i believe

 

That is a heck of a good question....I went to my local pick your part salvage yard and got a handful of different thickness shims off several vehicles. This can be a pain if you're not into doing this because you have to remove the tire and the brake caliper bracket.

 

ABS light

I'm also having a ABS issue with my 04 trailblazer ABS light is on, stopping is fine, however when i hooked up to a scanner and monitored the wheel speed 3 of the four wheels were reporting the correct MPH but the right front was only showing 3MPH which is what they all reported at stop. I have tried 2 new sensors and still have the issue, I have a new hub but before i go through the work of replacing it i have a question, if i disconnect the hub and just hook up my new one without installing it should the light go off at start?

 

Just plugging it in should work, after all, it's just an electrical connection. I don't know if you'd have to do a reset on the codes though.

 

abs issue

Does anyone know where the ABS connectors are under the hood?

 

Just follow the cable coming off the hub. You'll have to remove the tire to get inside the wheel well where it plugs in. It's not really hard to find with the wheel off and having access inside the wheel well.

 

ABS

Moderator you were right :thx just replace the hubs and save time and $$$. Had tried a couple sets of sensors and they just weren't reporting right and driving me and the ABS carzy. Just incase anybody else wants to know the sensors wind up connecting under the car drivers seat right by the air pump.

 

Anyone know the part number for the ABS sensor by itself? I have Duralast hubs with only 15K on them replaced in March 2013. Thinking of trying to test the sensor first.

 

Still haven't fixed my low wheel speed braking issue as it is now happening so infrequently, but still happening. Plus it has been closed as heck here in Chicago. Is it possible to simply replace the wheel speed sensors rather than the entire hub? I see them for sale, but not sure if there are different hookups.

Also my ABS light only comes on when I first start the car. By the time I reverse out of my driveway and then put it in drive in the street, the light goes out within seconds of driving forward. Does this help to diagnose anything from other's experiences? Wet weather seems to bring this out a bit more too, but it may just be my imagination. I can go days/weeks with no issue at all, then all of a sudden I may get the pedal pulse and odd straining noise. When I first start the car on cold mornings I get the straining noise VERY loud. I'm worried it may be the ABS module itself as it sounds like it is trying to do the ABS initialization check like the newer Acadias have at like 20mph.

Thoughts?

 

To verify the correct part number for any part on your GM vehicle, go to the following website:

http://www.gmpartsgiant.com/Page_Product/CheckPart.aspx

 

Hmmm!

Your pulsing issue sure sounds like the same thing I had, which was resolved by cleaning the rust from under the ABS sensors. The ABS light issue doesn't jive with the symptoms I had. My light never came on. Still, given the relative ease of checking the sensors I'd go there first before tearing into the rest of the system.
However, your hubs are relatively new, so it's not likely, although not impossible, that the sensor spacing has been thrown off so soon. Many people have mentioned that the only hubs worth buying are the Timkens due to quality issues with some of the other brands, including ABS issues.

BTW, last fall my left wheel bearing went out (120k miles) so I ended up replacing the hub anyway. Upon the recommendation of my mechanic friend I ordered Timken and upon the recommendation of folks here on Trailvoy I got them from Rock Auto for only slightly more than the discount brands.

Best of luck.
p.s What part of town/suburbs?

 

Just took off the ground that is under the drivers door and cleaned off all the rust. Light still came on when I started it up. I haven't driven it yet as I also replaced water pump and fan clutch this afternoon. (next up a trans leak at the oil cooler line...ugh).

I'm in La Grange Park, so not far from you in Berwyn. :thumbsup: