ABS question

[chrisinkanata]

In the last few weeks I have noticed that the ABS seems to activate in the seconds just prior to coming to a complete stop. Dry pavement, very low speed and it is just one pulsation or activation that can be felt in the brake pedal. I'm thinking one wheel sensor is telling the BCM that the wheel is not turning and with that an ABS activation. No other symptoms.

Anyone see this before?

Thanks,

Chris

[DmaxMaverick]

Get it to your dealer. There is a TSB, and silent recall, for ABS front wheel sensor corrosion. The symptoms are exactly as you describe.

[chrisinkanata]

Well, I call the dealer this morning and they advise me the VIN (1GTHC23112F228812) of my truck is not covered by the recall, so I have to pay for it. Little disappointed in that. I understand from what I've researched that the job is the removal, cleaning, and lubricaton of all mounting surfaces for the front sensors.

DmaxMaverick - Are you able to shed any light on that please?

Thanks,

Chris

[DmaxMaverick]

Yours is included in the VIN range. I don't know what your dealer is seeing, but it's pretty clear to me.

Recall Bulletin # 05068B - (04/21/2006)
2002/Cheverolet/Silverado/2F100022 to 2F249730 (last 8 digits of VIN....your is 2F228812).


General Motors has decided that a defect, which relates to motor vehicle safety, exists in certain 1999-2002 Chevrolet Silverado, 2000-2002 Chevrolet Tahoe, Suburban, 2002 Chevrolet Avalanche, 1999-2002 GMC Sierra, 2000-2002 GMC Yukon, Yukon XL vehicles located in the areas shown. These vehicles may have a condition permitting corrosion to occur between the front hub/bearing assembly and the wheel speed sensor. If the brakes are applied while the vehicle is traveling at a speed of greater than 6 km/h (3~7 mph) but less than 16 km/h (10 mph), the corrosion may cause an unwanted anti-lock brake system (ABS) activation. If this condition occurred where stopping distance is limited, a crash could occur.
I don't have the Canadian recall bulletin (if there is one, and if it's any different), but your VIN is in the range, nonetheless. The bulletin lists problem US states, but your location is well north of these, and should undoubtedly apply. There were no Canadian exclusions that I could find in the bulletin.

Take this info back to the dealer. If you still get guff from them, I can email you the correction procedure. It isn't too difficult, but will require removal of the wheel, brake calipers and hub (time consuming). I recently did a wheel bearing/hub replacement, and there was no indication of the problem, but I'm in California. New hubs have a new sensor included in the assembly, which is why they get your firstborn for one.

Also, it may only apply to US complaints but there is a NHTSA (National Highway Transportation Safety Administration) case on this, but you may have something similar in Canada....NHTSA CAMPAIGN ID NUMBER: 05V379000 MFG'S REPORT DATE: August 29, 2005....When a dealer balks on a safety issue, all that is usually needed is a referrence to a NHTSA case to put a fire under their butt.

Be sure to let us know what happens.

[chrisinkanata]

Well, after much discussion with GM, they decided they will cover it. The trucks been at the dealer for two days. I go to get it this afternoon and am told they can't do it because they can't get the front rotors off. They're afraid they'll wreck them because they're seized onto the hubs. I just say forget it...it's far less frustrating to do it myself.

So, DmaxMaverick, could I take you up on your offer please. If you could send me the procedure at clungstrass@sympatico.ca, I'd really appreciate it.

Thanks,

Chris

[DmaxMaverick]

Well, after much discussion with GM, they decided they will cover it. The trucks been at the dealer for two days. I go to get it this afternoon and am told they can't do it because they can't get the front rotors off. They're afraid they'll wreck them because they're seized onto the hubs. I just say forget it...it's far less frustrating to do it myself.

So, DmaxMaverick, could I take you up on your offer please. If you could send me the procedure at clungstrass@sympatico.ca, I'd really appreciate it.

Thanks,

Chris

I'd insist they do it. Obviously, they already got the approval. I'd tell them, "you break it, you bought it." It's their problem, not yours. The reason the rotors are seized on there is the exact same reason you are having a problem in the first place. Corrosion. If they can't get them off, you will have the same problem, but...."you break it, you bought it." If they are that bad off, the hubs may have to be replaced anyway, and if they do it, they'll have to buy the hubs, because the sensors are integrated. Stand your ground. If you don't get satisfaction, contact Canada's version of the NHTSA. They can put certain pressure on your dealer (and GM) to make right a problem they've already acknowledged as being their responsibility.

[Xmas1]

I have the same problem with my truck. ABS kicks in at low speeds just as described. My problem is that mine is an '03, not covered in the recall. About two months ago I had to replace the drivers side hub assembly because the bearings were shot, the new one was complete with the ABS sensor. R&R only took about 45 min. and I got a good deal on the parts, so it wasn't too bad. I first thought the problem could have been the new sensor so I tried the original sensor but I still have the problem.

Can someone explain exactly what to look for. After reading here about the problem I checked the passanger side and there is rust under the sensor but not where the screw holds it in place, only around the hole in the hub. Is it an electrical grounding problem or something else? The "spline" or teeth inside look fine and I didn't see any other issues except as described.

Any help would be great because I really don't want to buy another hub assembly to correct the problem.

[chrisinkanata]

The dealer as well as the regulatory authority here in Canada, Transport Canada, will do nothing about my issues so I'll have to do it myself. I have determined that once the rotor comes off, it's really very straightforward. Remove the sensor, clean up the mounting surface, a very thin application of silicone grease and re-assemble.

Hope it's at easy as it sounds.

Chris

[chrisinkanata]

Finally got around to this job. Not quite as straight forward as it seemed. I've been reading some other threads here about the removal of the rotors, calipers etc. and how easy it is. Not if they're corroded it isn't! No real issues getting the caliper mounting bolts outs. Lots of muscle involved but I've seen worse. BIG problem was getting the rotors off. Must be the salty road environment up here in Ontario. Man, were they a B****! Dealer was right, they were ruined in the removal process. Not really a big deal as the inside friction surfaces were so corroded as to likely not have been salvagable even with turning them. I was really worried about the hubs, but in the end, it worked out ok. Very carefully remove the sensors as they are fairly snug in the bores, clean everything, put it back together with new rotors and pads (almost 100K miles and the pads were still at about 50%). Away I go....but steady ABS light. Check the continutiy of the front sensors and sure enough, the left front is open. Take the left front apart again (no problems this time....actually about 5-6 minutes from the time the wheel was off 'til I was looking at the sensor in the hub). Take the sensor mounting bolt out and the top of the sensor is sheared off, leaving the magnet and coil in the bore. I had been so careful putting it back together, but I dropped the ball somewhere. Anyway, I took the hub off for easier access, spend about 30 min. playing around and in the end, got it all out ok. Install a new sensor, re-assemble and it's good to go. Original issue resolved.

Had everything gone as planned, it would have been about an hour job to do both sides but then, when do things go as planned. Be aware.....those ABS sensors are fragile!

Chris

[DmaxMaverick]

It's great to hear you got 'er fixed.

Do you have a BBB (Better Business Bureau) in your area? I would sure make a lengthy complaint if you do. At the very least, make a complaint with GM. That dealer is incompetent. "We can't fix your truck under warranty because it is too hard"........Waaaaa....sniffle.....

Would they have done it if you were just a paying customer? You bet. I'd hate to see what they do to their other customers.

[Aussie9]

Hi friends

Don't mean to jump in on the ABS problem thread, NOT sure if I am in the right spot - but this is my first post in any Forum & I'm from Australia so we can do things upside down here. Please direct me...There is little help from dealers here in Australia regards Suburban so i'm hoping to bounced off you experienced folk where Suburbans are a way of life with you good people. ( I've been to your wonderful country with my wife & 7 children 3 times now - that's where I first drove & learn't about the wonderful Suburban to accommodate my tribe...
ABS PROBLEM 98 6.5L Turbo Diesel Suburban :
My ABS light comes on intermittently, the ABS kicks in at walking pace unpredictably when I hardly touch the brake & the car jumps forward a couple of feet. After a Tech 2 scan the RH front wheel sensor was replaced but the above problem still remains. Please advise... Thanks from the Aussie Downunder.

[a5150nut]

Aussie99, My 94 PU was doing the same only in stop and go traffic. Makes for some exciting moments! Turned out to be the VSB sensor on the back of the transfer case. Transfer case was ready to be rebuilt, full of metal filings. They had collected on the magnetic tip of the sensor and would bridge the gap on the reluctor ring telling the ABS all was stopped. If you don't have rear wheel sensors it would be easy to check. Pull the sensor and see if it is covered with filings.

Almost forgot, Welcome to TDP!