|
| Search | Car Forums | Gallery | Articles | Helper | Air Dried Fresh Beef Dog Food | IgorSushko.com | Corporate |
|
#1
08-08-2011, 02:36 PM
|
|||
|
|||
|
ABS always engaging
Truck is a 2007 Silverado (Classic) with 5.3V8. 39k miles. Great truck until recently.
Recent issue when stopping the vehicle. About 75% of the time, at speeds between 5-10mph, the pedal pulses just like the ABS is engaging as it would normally do on ice or snow, and increases stopping distance. I've checked the wheel sensor connectors (one on each frame rail). Both have good, tight connections but I disconnected and cleaned anyway. Would appreciate any thoughts and most importantly if this is under warranty. Seems like a major safety issue to me since the vehicle takes longer to stop. thanks, RPG 
|
|
#2
08-08-2011, 03:33 PM
|
||||
|
||||
|
Re: ABS always engaging
Quote:
As per TSB on slow speed abs kicking in. If that fails to help. You need to get the ABS code and read out what the speed sensors are doing on a ABS capable scanner. All speed sensors should read out same mph with no drop outs. For more help. Post back code no.
__________________
Remember proper testing gives us the answer to many problems. MT
|
|
#3
08-08-2011, 05:16 PM
|
||||
|
||||
|
Re: ABS always engaging
This problem will not always set a code, also, watching individual speeds will not always show a drop out. The scanner may not update fast enough to show speed drop out. If problem persists after sensor clean, you need to find a scanner that will show all abs data, this way you can watch the individual solinoids. By watching which one engages first you will be able to tell which sensor is dropping out. This is the best way I have found to isolate whick sensor is the problem. Good luck!
|
|
#4
08-08-2011, 07:08 PM
|
|||
|
|||
|
Re: ABS always engaging
Quote:
what causes this is rust on the hub mounting surface or the hub bearing is bad. you could have all kinds of ABS issues...your issue however is the ABS activation at slow speeds. you do not need a 2ooo.oo scanner OEM licensed to check the sensors.. with a voltmeter set to ac volts 1 or 2volts range measure the sensor voltage at the connector while you rotate the hub with your hands at a good rate ..the voltage should be over 350 MV AC ...OR .35 VOLTS AC OR HIGHER.... IF YOU FIND THAT ONE SIDE IS LOW REMOVE THE SENSOR..spray with penitrating oil and let it soak ...rotate gently to remove...if the grease in the hub is red your bearing is shot...if the grease is blue try to file down the rusted hub sensor mounting surface then repeat the test on the voltage... If you find no problems as I discribed here then you have a very weird problem...which could cost alot to repair..this would mean most shops would replace everything ...this would be bad...
|
| The Following User Says Thank You to j cAT For This Useful Post: | ||
rpg (08-08-2011)
| ||
|
#5
08-08-2011, 08:03 PM
|
|||
|
|||
Re: ABS always engaging
thank you everyone for the excellent information. I'll post back results.
btw, no ABS codes on a scan. Just a PO449 error (EVAP SOLENOID). Gee, and everything was going so well with this truck RPG
|
|
#6
08-08-2011, 08:29 PM
|
|||
|
|||
|
Re: ABS always engaging
do yourself a favor and pull the abs fuse while driving untill you find out whats causing it. The brakes will work with the ABS fuse out, however if you slam them it will skid, easier to deal with than the brake failing due to ABS going off when not bneeded casuing you to hit someone or something, like so many have had happen.
__________________
4x4Junkie 2012 silverado 1500 ext. cab LT Z71 4x4 with allstar package 5.3L V8 Flexfuel with 6 speed AT Onstar / Sirius XM Factory Tow Package Electric Brake Controller Silver Ice Metallic 265/65/18 Wifes Vehicle 2014 Kia Sorento EX AWD 3.3L V6 Toys 2007 Yamaha VStar Silverado 1086cc 45 degree vtwin Grey and Silver GPS positioning locator installed
|
| The Following User Says Thank You to 4x4junkie For This Useful Post: | ||
rpg (08-08-2011)
| ||
|
#7
08-09-2011, 08:14 AM
|
|||
|
|||
|
Re: ABS always engaging
Quote:
|
|
#8
08-09-2011, 08:19 AM
|
|||
|
|||
|
Re: ABS always engaging
"I forgot to mention IF you find NO ABS CODE this adds to the sensors/or hub being the cause of the issue you have ......with my test proceedure you will locate if its the rusty hub or the hub bearing is shot".
I_Cat, thanks very much. I'll dig into it tonight. One question. This is a 2 wheel drive vehicle (1500) so I assume there isn't a hub bearing on the front discs, just the traditional two piece Timken bearings on each wheel. Or is there some additional support/bearing that you're referring to? I admit I haven't done any brake work on the vehicle yet, due to the low mileage. RPG
|
|
#9
08-09-2011, 08:31 AM
|
|||
|
|||
|
Re: ABS always engaging
Quote:
the sensor should be similar just you don't have a hub like the 4wd model..I would not expect the front bearing to be bad.. at this mileage I would clean and re grease them while your in that area... I have always regreased the front wheel bearings on my rear wheel drive vehicles every 50,ooomi. had one failure at 250,ooomi on my 1983. how do you like the strut design with this vehicle ? are they holding up ?
|
| ||||||||||||||||||||||||||||||||||||||
 |
POST REPLY TO THIS THREAD |
 |
|
|
