1986 ABS challenge
Thread Starter
Racer
Joined: Jul 2006
Posts: 420
Likes: 1
From: Zolton NJ
1986 ABS challenge
The system has malfunctioned. The symptom is as follows: vehicle started, when brake peddle is applied before putting vehicle into gear, the ABS cycles multiple times then ABS light stays on. The vehicle has an upgraded C5 system with all new parts. The challenge was there before the system upgrade.
I have searched the archived post. The results still leave me with questions. What has been your experience in being able to repair the same problem in your 1986. How much did it cost for the repair. Thank you.
I have searched the archived post. The results still leave me with questions. What has been your experience in being able to repair the same problem in your 1986. How much did it cost for the repair. Thank you.
Race Director
Joined: Jan 2008
Posts: 16,028
Likes: 170
From: oregon
you need the breakout box for an 86, they do come up on ebay from time to time though. only 90 and newer allow code reading. mentioning of codes, the abs system does not always tell the truth. one way i've found to narrow it down to a bad ebcm is to fix one of the codes, see if it clears, if it does not, the ebcm is likely dead. usually wheel speed sensors, the pump or ebcm are the faults. the pumps are the most rare thing to die. sensors and ebcms die often. sometimes dying ebcms do what the OP suggested. after a few weeks they just die all togeather and nothing cycles. the last ebcm i reparied had codes that pointed at the pump. wrong. oh yes, one last thing is a relay. there is 1 relay that is famous for going out in c4's it's a little plastic jobber off to the side of the abs compartment. corvettefever has an online article on how you can test this.
Le Mans Master
Joined: Jan 2003
Posts: 5,858
Likes: 7
From: Santa Maria CA
Race Director
Joined: Sep 2000
Posts: 12,182
Likes: 1
From: Partying with the Cowboys cheerleaders in Mt. Olive, New Jersey
'86 do not have ABS codes to be pulled. Mine started to malfunction a few months ago. I started simple, pull all the wheel speed sensors, cleaned them, then put them back. Still no go, one of the rear ones looked bad however. It's definitely the culprit.
I've also tested the relays behind the driverseat under the storage compartment, they're all good. I even swapped the relays with new ones. Still no go, so the initial diagnose is right, bad sensors. I've had a really tough time locating these freakin' wheel speed sensors.
I've also tested the relays behind the driverseat under the storage compartment, they're all good. I even swapped the relays with new ones. Still no go, so the initial diagnose is right, bad sensors. I've had a really tough time locating these freakin' wheel speed sensors.
Race Director
Joined: Aug 2000
Posts: 14,130
Likes: 7
Cruise-In II Veteran
I had a bad wheel sensor do this.You can always pull the abs fuse to disable the abs until you get it fixed.The abs light will remain on.You can even pull the bulb.Disabling the abs will not affect the brakes in any way,just render it a vette without it,sans the 84-85 cars.
Just wont have abs working until you fix it correctly.
Its also normal,for the abs to do a self test everytime you start the car and drive either 5 mph in fwd or reverse,but it wont cycle as much as you said nor throw the light.It usually buzzes a few seconds and is done.
I said that in case someone didnt know.
Just wont have abs working until you fix it correctly.
Its also normal,for the abs to do a self test everytime you start the car and drive either 5 mph in fwd or reverse,but it wont cycle as much as you said nor throw the light.It usually buzzes a few seconds and is done.
I said that in case someone didnt know.
Le Mans Master
Joined: Apr 2005
Posts: 6,413
Likes: 9
From: The Old Dominion
No codes, man that sucks... Just my two cents, but if it turns the light on after cycling the pump and the car not moving, I wouldn't think it would be wheel sensors. It cycles the pump to test *something* presumably. I don't know enough to know what, but I guess that's where I'd be looking in the FSM.
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Race Director
Joined: Jan 2008
Posts: 16,028
Likes: 170
From: oregon
the dealer breakout box for the 86-89 cars sells on ebay under $100 frequently. if you own an early car it might be a good investment. you also can test the sensors with an ohm meter. the FSM has the proper range for the readings. if you have 1 bad one it should be out of wack compared to the others.
Thread Starter
Racer
Joined: Jul 2006
Posts: 420
Likes: 1
From: Zolton NJ
86Pacer,
where did you purchase the ABS computer for $26?
I contacted a local Chevrolet dealer service department that stated they do not work on Corvettes that old because they can not offer the 12 month warranty on the work. I contacted the parts department that stated that no Chevrolet dealer in the US has the part. If they had the part it would be $1,200. The parts associate said he had the same problem with his 1991 Corvette and after the dealership‘s master mechanic replaced all the relays and sensors it turned out to be the ABS computer.
No luck with Summit, Pep Boys, Advance Auto, NAPA wanted $750.00 for the part.
Contemporary Corvettes wanted $350.00 for a used one. I found a company “ebcmdirect.com” in Florida that will rebuild my ABS computer with life time warranty for $369.95 or sell a rebuilt one for $469.95 out right.
My plan right now is to send the ECBM (ABS computer) in for a rebuild, after a Custom car show next week in OC MD Thursday - Sunday. If you live close you should try to make it (3,000 + vehicles) great show.
I appreciate everyone who responded to this post. I will keep you up dated. Thanks!
where did you purchase the ABS computer for $26?
I contacted a local Chevrolet dealer service department that stated they do not work on Corvettes that old because they can not offer the 12 month warranty on the work. I contacted the parts department that stated that no Chevrolet dealer in the US has the part. If they had the part it would be $1,200. The parts associate said he had the same problem with his 1991 Corvette and after the dealership‘s master mechanic replaced all the relays and sensors it turned out to be the ABS computer.
No luck with Summit, Pep Boys, Advance Auto, NAPA wanted $750.00 for the part.
Contemporary Corvettes wanted $350.00 for a used one. I found a company “ebcmdirect.com” in Florida that will rebuild my ABS computer with life time warranty for $369.95 or sell a rebuilt one for $469.95 out right.
My plan right now is to send the ECBM (ABS computer) in for a rebuild, after a Custom car show next week in OC MD Thursday - Sunday. If you live close you should try to make it (3,000 + vehicles) great show.
I appreciate everyone who responded to this post. I will keep you up dated. Thanks!
Le Mans Master
Joined: Jan 2003
Posts: 5,858
Likes: 7
From: Santa Maria CA
Ebay. It was a low starting price with no reserve. I actually won it for the starting price because it's kinda rare someone is looking for one, so competition is low.
Right now there is an ABS pump with wiring harness, relays, and tray on ebay for $79.99 Item# 180293296491
The ABS computer on ebay runs about $40. If you keep an eye out, you can get one for even less than that.
For what you will spend on a Kent Moore ABS tool, or to send yours out for repair, you can just replace the pump and computer with a good used unit off ebay and be done with it. But go through the troubleshooting steps in the shop manual first. You might not even need this stuff.
Top off brake fluid level.
Check "Brake", "Guages", "Stop/Haz", and "INJ 1" fuses
More:
Most dealers don't even carry this tool anymore because these cars are too old. Again, for what you will spend to have this tested even if they did, you can just buy another good unit on ebay.
My diagnosis was pretty straight forward. My ABS compartment had an old waterline. Everything got submerged underwater, so everything (computer, relays, pump) was trashed. My ABS works line new with the unit I picked up on ebay.
Right now there is an ABS pump with wiring harness, relays, and tray on ebay for $79.99 Item# 180293296491
The ABS computer on ebay runs about $40. If you keep an eye out, you can get one for even less than that.
For what you will spend on a Kent Moore ABS tool, or to send yours out for repair, you can just replace the pump and computer with a good used unit off ebay and be done with it. But go through the troubleshooting steps in the shop manual first. You might not even need this stuff.
Top off brake fluid level.
Check "Brake", "Guages", "Stop/Haz", and "INJ 1" fuses
More:
My diagnosis was pretty straight forward. My ABS compartment had an old waterline. Everything got submerged underwater, so everything (computer, relays, pump) was trashed. My ABS works line new with the unit I picked up on ebay.
Last edited by 86PACER; Oct 1, 2008 at 10:17 PM.
Burning Brakes
Joined: Jan 2007
Posts: 853
Likes: 0
From: Slinger WI