ABS Light Always ON 1996 Chevrolet Cheyenne 4x4
tinkering
11-25-2011, 06:07 PM
The ABS light is ALWAYS ON. The front brakes grab really bad when the truck has been sitting for a few days, or when it is rainy driving conditions. Where do I start?
gremlin96
11-25-2011, 07:28 PM
you need to go to a auto parts store and see if they have a scanner that can read the abs. get the codes then start trouble shooting from there. you can clean up the sensors and see if that fixes it. but you will need to reset the codes. check for broken wires and crud in the connectors.
tinkering
11-25-2011, 08:05 PM
you need to go to a auto parts store and see if they have a scanner that can read the abs. get the codes then start trouble shooting from there. you can clean up the sensors and see if that fixes it. but you will need to reset the codes. check for broken wires and crud in the connectors.
Where are the sensors, and how do you clean them? Do you need the scanner to reset the codes? Broken wires and crud in the connectors at the wheels?
Where are the sensors, and how do you clean them? Do you need the scanner to reset the codes? Broken wires and crud in the connectors at the wheels?
autojoe
11-26-2011, 08:30 AM
most auto parts stores cant read these codes with their generic scan tools.these codes are stored in the body control module.check your wheel speed sensors that are attached to each wheel on the inside.check electrical connectors and wiring to connectors.make sure no broken teeth on hub and no builup of dirt.lots of people dont have money to fix or dont like abs so they disconnect fuse or abs module connector.I would check above items and if that is ok you would have to take to a shop one that specializes in electrical diagnostics and they would read codes and also on their scan tool check the wheel sensors if operating.you need enhanced scan tool for working on abs and bi-directional controls.you are very limited on what you can do or check without proper testing equipment.
autojoe
11-26-2011, 08:32 AM
also the sensors have 2 wires going to them.the only wires at wheels.
j cAT
11-26-2011, 04:46 PM
Where are the sensors, and how do you clean them? Do you need the scanner to reset the codes? Broken wires and crud in the connectors at the wheels?
the sensors need be checked with an ohm meter. I forget what amount but 1000-2000 ohms or so. If open this is what I had with the 94 s10 pu. this is expensive stuff. I just put the black tape over the dash amber light.
brakes you should remove the rear drums and see if the shoes are worn/wearing only at the top if so the drums are too worn. also with a big ridge on the drum edge this is indicating its worn.
GM had many problems when they started out trying to get ABS working correctly in vehicles. I have had many years experience with the ABS back in the 1970's with larger vehicles that had abs systems[not GM]. GM did a very poor cheapo job with this 90's abs experiment.
the sensors need be checked with an ohm meter. I forget what amount but 1000-2000 ohms or so. If open this is what I had with the 94 s10 pu. this is expensive stuff. I just put the black tape over the dash amber light.
brakes you should remove the rear drums and see if the shoes are worn/wearing only at the top if so the drums are too worn. also with a big ridge on the drum edge this is indicating its worn.
GM had many problems when they started out trying to get ABS working correctly in vehicles. I have had many years experience with the ABS back in the 1970's with larger vehicles that had abs systems[not GM]. GM did a very poor cheapo job with this 90's abs experiment.
autojoe
11-26-2011, 06:27 PM
resistance doesn't always work.best way to test is with a dso.
j cAT
11-27-2011, 07:08 AM
resistance doesn't always work.best way to test is with a dso.
well on the 1994 S10 the manual stated the resistance check. with the pickup coil open no need to go further . what I also found was the plastic enclosure had a small crack, this is why the coil corroded open . with the coil open no way any output is possible.
well on the 1994 S10 the manual stated the resistance check. with the pickup coil open no need to go further . what I also found was the plastic enclosure had a small crack, this is why the coil corroded open . with the coil open no way any output is possible.
autojoe
11-27-2011, 06:52 PM
what manual?haynes?dynamic testing is always better.resistance can vary with temperature.best way is to retrieve abs codes from the body control module and use an enhanced scan tool to pinpoint problem area.
j cAT
11-27-2011, 07:23 PM
what manual?haynes?dynamic testing is always better.resistance can vary with temperature.best way is to retrieve abs codes from the body control module and use an enhanced scan tool to pinpoint problem area.
when the abs sensor is open / no resistance as in a open circuit this device can not work no how no way. straping on a scanner /scope /voltmeter etc is not going to get any output.
with code retrival this helps narrow down where the problem is . DIY backyard mechanics most times lack this abs expensive test equipment. especially the ABS capabile scanner which requires GM diagnostic abilities. this why testing with an ohmmeter/voltmeter and disassembly of these very failure prone sensors usually works out, with the issues he has posted here.
taking a 1996 vehicle to the dealership with this repair could cost more to repair than the actual vehicle value.
finding a repair shop with the ability to read the ABS code could be a problem .
110% of these vehicles of this vintage have these issues if still on the road today.
when the abs sensor is open / no resistance as in a open circuit this device can not work no how no way. straping on a scanner /scope /voltmeter etc is not going to get any output.
with code retrival this helps narrow down where the problem is . DIY backyard mechanics most times lack this abs expensive test equipment. especially the ABS capabile scanner which requires GM diagnostic abilities. this why testing with an ohmmeter/voltmeter and disassembly of these very failure prone sensors usually works out, with the issues he has posted here.
taking a 1996 vehicle to the dealership with this repair could cost more to repair than the actual vehicle value.
finding a repair shop with the ability to read the ABS code could be a problem .
110% of these vehicles of this vintage have these issues if still on the road today.
autojoe
11-27-2011, 07:45 PM
that is why most of the time backyard mechanics cant fix their vehicles beacause you cant guess and proper test equipment is required to diagnose.you are right you can check minor things but most of the time it is something more.sometimes you have to bite the bullet and take to someone that has the knowledge and proper testing equipment.the days of shoemakering and backyard mechanics fixing their own vehicles are becoming obsolete.I used to be one long time ago and no own thousands of dollars in testing equipment which have to upgrade annually and also go to training classes on a regular basis to keep abreast of changes in field.
j cAT
11-28-2011, 07:22 AM
that is why most of the time backyard mechanics cant fix their vehicles beacause you cant guess and proper test equipment is required to diagnose.you are right you can check minor things but most of the time it is something more.sometimes you have to bite the bullet and take to someone that has the knowledge and proper testing equipment.the days of shoemakering and backyard mechanics fixing their own vehicles are becoming obsolete.I used to be one long time ago and no own thousands of dollars in testing equipment which have to upgrade annually and also go to training classes on a regular basis to keep abreast of changes in field.
these forums and many others out there provide much of the secret info that GM and the other vehicle manufactures deny to persons/small repair shops, looking to repair these vehicles.
It helps to have a good knowledge of electronics and electrical systems.
with no training in this area your at a great disadvantage. understanding the repair manual and acting on the tests to determine component defect/condition.
one thing I learned many years ago ....the computer/scanner /diagnosing machines can't fix the problem ! just gets you going in the correct direction ..
knowing what to look for is what these forums provide , rather than changing parts to determine defective component.
even dealerships do this ! perhaps its just to jackup the repair bill so manager gets bigger $$$$... or techs lack the basic electrical/electronic knowledge .
with these vehicles this issue has much internet info for DIY repair..
these forums and many others out there provide much of the secret info that GM and the other vehicle manufactures deny to persons/small repair shops, looking to repair these vehicles.
It helps to have a good knowledge of electronics and electrical systems.
with no training in this area your at a great disadvantage. understanding the repair manual and acting on the tests to determine component defect/condition.
one thing I learned many years ago ....the computer/scanner /diagnosing machines can't fix the problem ! just gets you going in the correct direction ..
knowing what to look for is what these forums provide , rather than changing parts to determine defective component.
even dealerships do this ! perhaps its just to jackup the repair bill so manager gets bigger $$$$... or techs lack the basic electrical/electronic knowledge .
with these vehicles this issue has much internet info for DIY repair..
jdmccright
11-28-2011, 01:06 PM
I have also seen where either the wheel bearings or the brakes are heated up enough to soften the plastic that the ABS sensors are embedded in. This can make them become misaligned or move to make contact with the reluctor ring and damage it. I don't know which is the cause, I've only seen the aftermath from a purchased vehicle.
777stickman
11-28-2011, 04:25 PM
Lots of good info & speculation in this tread. But until this guy takes the initiative to spend $40-50 for a shop to access the ABS system for codes and then post the code numbers here, it still remains speculation.
tinkering
03-08-2012, 06:03 PM
most auto parts stores cant read these codes with their generic scan tools.these codes are stored in the body control module.check your wheel speed sensors that are attached to each wheel on the inside.check electrical connectors and wiring to connectors.make sure no broken teeth on hub and no builup of dirt.lots of people dont have money to fix or dont like abs so they disconnect fuse or abs module connector.I would check above items and if that is ok you would have to take to a shop one that specializes in electrical diagnostics and they would read codes and also on their scan tool check the wheel sensors if operating.you need enhanced scan tool for working on abs and bi-directional controls.you are very limited on what you can do or check without proper testing equipment.
I don't see any wires or sensors in there. Do you have to take the rotor off pr something, to see it sensor? If I just undo all the connectors on the ABS control body, will the brakes work the old way? I know there are ways to spend money to get the ABS working but if they will work without ABS, that is fine with me. Brakes always worked fine for me before ABS came along...
I don't see any wires or sensors in there. Do you have to take the rotor off pr something, to see it sensor? If I just undo all the connectors on the ABS control body, will the brakes work the old way? I know there are ways to spend money to get the ABS working but if they will work without ABS, that is fine with me. Brakes always worked fine for me before ABS came along...
j cAT
03-08-2012, 06:14 PM
I don't see any wires or sensors in there. Do you have to take the rotor off pr something, to see it sensor? If I just undo all the connectors on the ABS control body, will the brakes work the old way? I know there are ways to spend money to get the ABS working but if they will work without ABS, that is fine with me. Brakes always worked fine for me before ABS came along...
get a repair manual or internet subscription to one . then after readings post back IF you have any questions.
call for a repair shop or parts store that can retrieve ABS failure codes then post whats going on.
if you cannot see any wires at the wheel hubs it is possible they were cut off/broke off................
get a repair manual or internet subscription to one . then after readings post back IF you have any questions.
call for a repair shop or parts store that can retrieve ABS failure codes then post whats going on.
if you cannot see any wires at the wheel hubs it is possible they were cut off/broke off................
tinkering
03-09-2012, 12:25 AM
get a repair manual or internet subscription to one . then after readings post back IF you have any questions.
call for a repair shop or parts store that can retrieve ABS failure codes then post whats going on.
if you cannot see any wires at the wheel hubs it is possible they were cut off/broke off................
The Chilton Manual I have here isn't worth a dime as far as brakes/ABS info goes.
That's right, I have found that the drivers side sensor wire has been taken off. The passenger side is still there. That would explain why the ABS performance is so out of whack; so I pulled the ABS fuse out of the under-hood panel (like 'autojoe' said some guys do who don't like ABS). I will undo the ABS module connector tomorrow, to see if the ABS dash light goes out; If not, I will use black tape over it like you did :). I also tried to 'reset' the main computer (by turning ignition switch to 'on', undoing neg battery cable, waiting a bit, turning ignition off, putting neg cable back on) to see if the ABS dash light would go out... :lol2: no such luck.
The brakes seemed to work OK like this on the road test. I will be able to tell better when the rain starts up again tomorrow (the front brakes would grab nasty in the rain). If it works, I don't mind bypassing the ABS. This truck has been used to ply the mountain goat path to town for 15 years; it is a beater and yes, I don't want to spend a ton of money and time on it. The front pads and rotors are good. I will check out the rear shoes and drums next; there is a fair bit of brake howl coming out of there.
call for a repair shop or parts store that can retrieve ABS failure codes then post whats going on.
if you cannot see any wires at the wheel hubs it is possible they were cut off/broke off................
The Chilton Manual I have here isn't worth a dime as far as brakes/ABS info goes.
That's right, I have found that the drivers side sensor wire has been taken off. The passenger side is still there. That would explain why the ABS performance is so out of whack; so I pulled the ABS fuse out of the under-hood panel (like 'autojoe' said some guys do who don't like ABS). I will undo the ABS module connector tomorrow, to see if the ABS dash light goes out; If not, I will use black tape over it like you did :). I also tried to 'reset' the main computer (by turning ignition switch to 'on', undoing neg battery cable, waiting a bit, turning ignition off, putting neg cable back on) to see if the ABS dash light would go out... :lol2: no such luck.
The brakes seemed to work OK like this on the road test. I will be able to tell better when the rain starts up again tomorrow (the front brakes would grab nasty in the rain). If it works, I don't mind bypassing the ABS. This truck has been used to ply the mountain goat path to town for 15 years; it is a beater and yes, I don't want to spend a ton of money and time on it. The front pads and rotors are good. I will check out the rear shoes and drums next; there is a fair bit of brake howl coming out of there.
j cAT
03-09-2012, 08:38 AM
if you look up the cost to repair these front sensors I found too expense for a vehicle this old. this type of ABS system being so failure prone causes more trouble than it prevents ,with these mid 90's vehicles.
on the rear drum brakes if the shoes are worn mostly at the top ,,,, THIS means the drums are too worn . with need drums and shoes the vehicle will stop much better.
I have found that if someone adjusted the parking brake cable to compensate for drum wear this can be a problem to adjust the park brake cable correctly. the cable should have some slack////fully released !!!
buy some powerful rust pretrating oil. not wd-40.
on the rear drum brakes if the shoes are worn mostly at the top ,,,, THIS means the drums are too worn . with need drums and shoes the vehicle will stop much better.
I have found that if someone adjusted the parking brake cable to compensate for drum wear this can be a problem to adjust the park brake cable correctly. the cable should have some slack////fully released !!!
buy some powerful rust pretrating oil. not wd-40.
tinkering
03-09-2012, 09:45 AM
if you look up the cost to repair these front sensors I found too expense for a vehicle this old. this type of ABS system being so failure prone causes more trouble than it prevents ,with these mid 90's vehicles.
on the rear drum brakes if the shoes are worn mostly at the top ,,,, THIS means the drums are too worn . with need drums and shoes the vehicle will stop much better.
I have found that if someone adjusted the parking brake cable to compensate for drum wear this can be a problem to adjust the park brake cable correctly. the cable should have some slack////fully released !!!
buy some powerful rust pretrating oil. not wd-40.
The rain is here again so I am waiting for the sun as there is no garage here. I am anxious though to get those drums off for a look. I know shoes normally wear more at the top but I hear you; I will change the drums if the shoes show unseasonable wear concentrated at the top (or if there are unreasonable grooves or high shoulders). The parking brake pedal has quite a bit of travel but that doesn't mean it hasn't been over adjusted in the past. Thanks for drawing my attention to leave slack on the cable when it is released; I have always felt unsure about that; I have probably set some too tight in the past. It pays to talk!
What are the brand names of some powerful rust penetrating oils?
on the rear drum brakes if the shoes are worn mostly at the top ,,,, THIS means the drums are too worn . with need drums and shoes the vehicle will stop much better.
I have found that if someone adjusted the parking brake cable to compensate for drum wear this can be a problem to adjust the park brake cable correctly. the cable should have some slack////fully released !!!
buy some powerful rust pretrating oil. not wd-40.
The rain is here again so I am waiting for the sun as there is no garage here. I am anxious though to get those drums off for a look. I know shoes normally wear more at the top but I hear you; I will change the drums if the shoes show unseasonable wear concentrated at the top (or if there are unreasonable grooves or high shoulders). The parking brake pedal has quite a bit of travel but that doesn't mean it hasn't been over adjusted in the past. Thanks for drawing my attention to leave slack on the cable when it is released; I have always felt unsure about that; I have probably set some too tight in the past. It pays to talk!
What are the brand names of some powerful rust penetrating oils?
Schurkey
03-09-2012, 12:46 PM
The ABS light is ALWAYS ON. The front brakes grab really bad when the truck has been sitting for a few days, or when it is rainy driving conditions. Where do I start?
First Guess: More than one problem.
I'd be looking for the front brake pads being contaminated or severely worn, if they're grabby.
ABS on a '96? I've got a Snap-On MT2500 v. 2.2 scan tool for sale that'll pull those codes (and way, way more)
http://www.garagejournal.com/forum/showthread.php?t=127858
First Guess: More than one problem.
I'd be looking for the front brake pads being contaminated or severely worn, if they're grabby.
ABS on a '96? I've got a Snap-On MT2500 v. 2.2 scan tool for sale that'll pull those codes (and way, way more)
http://www.garagejournal.com/forum/showthread.php?t=127858
j cAT
03-09-2012, 02:29 PM
The rain is here again so I am waiting for the sun as there is no garage here. I am anxious though to get those drums off for a look. I know shoes normally wear more at the top but I hear you; I will change the drums if the shoes show unseasonable wear concentrated at the top (or if there are unreasonable grooves or high shoulders). The parking brake pedal has quite a bit of travel but that doesn't mean it hasn't been over adjusted in the past. Thanks for drawing my attention to leave slack on the cable when it is released; I have always felt unsure about that; I have probably set some too tight in the past. It pays to talk!
What are the brand names of some powerful rust penetrating oils?
at the parts store ask the sales guy what products works best for rusted bolts.
the park brake cable with new shoes and drums will cause the cable to tighten up. if no slack this will wear out your shoes and drum.
drums also get bell shaped. the ridge is also an indicator of drum wear. the shoes wearing at the top is a big indication on all the drum brakes I have worked over the years.
when the front end dips on braking this is most always a poor brake effort in the rear. this will cause the front rotors to get overheated and distorted.
the park brake should hold the vehicle with 4-5 clicks on the pedal .
when the park brake pedal goes down too far then re-adjust the brake shoes.
use paint thinner to wipe down the drums and shoes before installing
What are the brand names of some powerful rust penetrating oils?
at the parts store ask the sales guy what products works best for rusted bolts.
the park brake cable with new shoes and drums will cause the cable to tighten up. if no slack this will wear out your shoes and drum.
drums also get bell shaped. the ridge is also an indicator of drum wear. the shoes wearing at the top is a big indication on all the drum brakes I have worked over the years.
when the front end dips on braking this is most always a poor brake effort in the rear. this will cause the front rotors to get overheated and distorted.
the park brake should hold the vehicle with 4-5 clicks on the pedal .
when the park brake pedal goes down too far then re-adjust the brake shoes.
use paint thinner to wipe down the drums and shoes before installing
tinkering
03-10-2012, 09:15 AM
First Guess: More than one problem.
I'd be looking for the front brake pads being contaminated or severely worn, if they're grabby.
ABS on a '96? I've got a Snap-On MT2500 v. 2.2 scan tool for sale that'll pull those codes (and way, way more)
http://www.garagejournal.com/forum/showthread.php?t=127858
The pads look good... clean and thick. I think the ABS sensor being gone was biggest contributor. Now for back brakes :)
I'd be looking for the front brake pads being contaminated or severely worn, if they're grabby.
ABS on a '96? I've got a Snap-On MT2500 v. 2.2 scan tool for sale that'll pull those codes (and way, way more)
http://www.garagejournal.com/forum/showthread.php?t=127858
The pads look good... clean and thick. I think the ABS sensor being gone was biggest contributor. Now for back brakes :)
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