ABS Issue

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ABS Issue

Postby autotraveler » Thu Sep 08, 2016 9:34 am

I'm traveling and have an ABS issue. Previously had a hard pedal condition. Following directions in another thread, jumped the ABS relay, confirmed that the pump was working, replaced relay, brake pedal came back. ABS and brake warning lights went off. Drove the car about 200 miles, condition returned. At the same time, rear air bags went down, could be unrelated as this has been an intermittent condition.

But at the same time the trip computer display started flickering. Arriving at my destination, Lompoc, CA, where I am now stuck, I checked the battery cables since I just replaced the battery, ground cable a bit loose so I tightened it. Still no brakes but air bags powered up, can hear the pump working. Checked the alternator with multimeter, output is 13.1 volts at the alternator.

What should I be looking for at this point given that initially the relay replacement solved the issue. Please post suggestions and solutions here but please email me direct at autotraveler1154@gmail.com.

Thanks everyone. I've left messages with local mobile mechanics (none have responded but it is only 630am here) to see if I can get a better diagnosis before going to a shop. Having anyone helping me narrow down the possibilities I think is a good idea, especially if someone has already experienced the same problem.
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Re: ABS Issue

Postby CDW6212R » Thu Sep 08, 2016 9:45 am

The 13.1 volts sounds low, unless the battery is fully charged and nothing is really running. I'd check into that charging more, turn some things on and see if it changes. It shouldn't get below 12.5 or so, but often it might ought to be nearer to 14v with little turned on. If the voltage doesn't get out of proper ranges, then it should be okay.

The air springs are unrelated to the brakes, unless it's an electrical issue affecting both(and the trip minder etc).
Don
1991 Red Special Edition, my 2nd SE, dead paint, DWS 255/45/17's on 95 Cobra wheels, and soon; DVD/Navi/backup camera, OBDII and the 347, before custom paint.
98 Mountaineer with Continental DWS 255/55/18's, big sway bars, custom brakes. Soon to be A4WD with XP8 bumpers and wing.

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Re: ABS Issue

Postby CDW6212R » Thu Sep 08, 2016 9:48 am

Does the ABS pump run when it should? If the brakes haven't been depressed it might not run at startup, but typically it does/should. While running the ABS pump should run after a number of pedal applications.

You don't want the pump to run continuously, so watch that and turn off the key to make it rest if necessary. After the pump runs there should be a usable brake pedal.
Don
1991 Red Special Edition, my 2nd SE, dead paint, DWS 255/45/17's on 95 Cobra wheels, and soon; DVD/Navi/backup camera, OBDII and the 347, before custom paint.
98 Mountaineer with Continental DWS 255/55/18's, big sway bars, custom brakes. Soon to be A4WD with XP8 bumpers and wing.

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Re: ABS Issue

Postby WHITEOXLSC » Thu Sep 08, 2016 11:58 am

Could possibly be a alternator or voltage regulator issue since so many things are being affected at the same time, as mentioned above the voltage reading seems a little low......
Check the voltage at the battery with the car off and then running, voltage should be around 14v or above when running. Check the battery grounds too, bad grounds in these cars can cause all sorts of weird stuff to happen.
Bruce
WHITEOXLSC
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1990 Regatta Blue LSC (newest addition aka Blu)
1986 Mark VII Silver LSC (sold, aka the Grey Ghost)
1990 Mark VII Oxford White LSC (new addition aka the WhiteOx)
1993 Ford Green Explorer Sport 2WD 4.0L V6 (daily driver do everything truck)(loaded first generation)
1988 Ford Blue/mostly rust brown Ranger 2.9L V6 STX P/U (Old faithful) (dead trans, 358XXX miles, sold)
1975 Oldsmobile Blue Omega Hatchback Coupe

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Re: ABS Issue

Postby autotraveler » Fri Sep 09, 2016 9:27 am

Here's an update.

Yesterday morning I jumped the 3 and 4 pins on the relay socket, the ABS pump came on. I reconnected the ABS relay, the pump operated and the brake and ABS warning lights went off, brake pedal returned to normal and I drove the car home, 250 miles without further incident. I may have a faulty or defective relay, AutoZone already has got me a replacement which I pick up today.

The trip computer screen remained flaky, totally off sometimes, flickering at other times. DTE function never has worked but even after being totally dark, the system retains ongoing average fuel economy. I assume there's a constant 12 volts going to the display to retain memory.

I'm going to have the alternator checked today, suspect that it will test out at 13.1 volts, which is marginal. But the alternator warning light has never come on.

Anyone experienced anything similar on the trip computer? Any possible solution? Could it be related to the low-voltage coming off of the alternator?

Thanks for any help provided.
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Re: ABS Issue

Postby CDW6212R » Fri Sep 09, 2016 12:50 pm

The trip computer is almost surely malfunctioning, at this age there are virtually none left working right. They can be rebuilt, contact Paul Protos about that. He also handles the AC unit, the radios and the overhead display. That isn't related to your ABS issue, unless the power really is out of range etc(wiring, alternator, or VR).

The relay you have had an issue with twice may be the problem, and at this age it should be replaced anyway. So replace it for sure, but also keep an eye(and ear) on the ABS lights and pump. If the problem happens again, I'd bet the terminals inside the relay connector are not fully seating to the relay. That's a rare possibility for any electrical connectors, but it does happen. There is a tiny plastic tip/arm inside each connector terminal slot, which engages and holds the terminals in place. Those plastic tips can break off, and then the terminal easily pushes out(but often will return once the terminal(such as a relay) is removed(thus they look fine)).
Don
1991 Red Special Edition, my 2nd SE, dead paint, DWS 255/45/17's on 95 Cobra wheels, and soon; DVD/Navi/backup camera, OBDII and the 347, before custom paint.
98 Mountaineer with Continental DWS 255/55/18's, big sway bars, custom brakes. Soon to be A4WD with XP8 bumpers and wing.

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Re: ABS Issue

Postby autotraveler » Fri Sep 09, 2016 3:32 pm

Things turning to crap right now. Brought the car in for tires this morning, brakes working fine. Pick up the car, hard pedal has returned and get this, jumping the 3-4 pins on the relay socket doesn't turn on the ABS pump. I can hear the airbag pump working fine.

What are the chances of the ABS pump going bad at this point?

The owner's manual mentions an underhood fuse link? If this is true, exactly where would it be located?

Further update now that the car is home.

Battery voltage (brand new battery, replaced battery on Monday)

Nothing on, car running at idle 12.89-13.27 volts at idle
A/C and lights on 12.52 volts at idle

Relay socket, car running, no accessories on, test light black lead connected to negative battery terminal

pin 1 -0.01 (confirmation of ground)
pin 2 13.35
pin 3 -0.01 (confirmation of ground)
pin 4 13.52
pin 5 -0.01 (confirmation of ground)

Pin diagram confirmation from this thread

viewtopic.php?f=12&t=6041#p52145

by

Re: 1990 LSC master cylinder
Postby K MANIAC ยป Tue Feb 28, 2012 11:05 pm

Unlike yesterday, when I jumped the 3 and 4 pins on the relay socket, the ABS pump came on. I reinserted the relay, and both the brake and ABS lights went off. I assumed that the system had reset, like with a code reader.

Right now I have the ground cable disconnected from the battery, hoping (keeping fingers crossed) that might reset the system. Probably wishful thinking.

I'm not all that mechanically inclined but I know 12-volt automotive from when I owned a car stereo store back in the 1980s and early 1990s.

This has become very frustrating, with these symptoms, what should I look at next?
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Re: ABS Issue

Postby WHITEOXLSC » Fri Sep 09, 2016 8:16 pm

If you jump pins 3 and 4 (and voltage is present) and the motor still does not run I would check the ground side of the motor circuit. From your negative side of the battery terminal you should see a smaller gauge wire come off of it and ground to the front header by the battery, check that it is not corroded, and it's clean and tight. Next continue to follow the wires to the compressor area, there should be a connector there (C103) Make sure this connection is good and not corroded. This two wire connector (shown below) is the main ground connector for many circuits and when it fails, it will cause all sorts of issues. (mine did I know). Also check that the ground on the front of the ABS unit is tight and corrosion free. Check for + 12v and ground at the pump motor itself. If there is a good voltage and ground at the motor wires, then the motor itself has failed :(
You do not have the required permissions to view the files attached to this post.
Bruce
WHITEOXLSC
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1990 Regatta Blue LSC (newest addition aka Blu)
1986 Mark VII Silver LSC (sold, aka the Grey Ghost)
1990 Mark VII Oxford White LSC (new addition aka the WhiteOx)
1993 Ford Green Explorer Sport 2WD 4.0L V6 (daily driver do everything truck)(loaded first generation)
1988 Ford Blue/mostly rust brown Ranger 2.9L V6 STX P/U (Old faithful) (dead trans, 358XXX miles, sold)
1975 Oldsmobile Blue Omega Hatchback Coupe

Proudly supporting ; Pick N Pull of the greater bay area, NAPA auto parts, Ebay, Suncore Industries, Johnny Franklin mufflers, and Paul Protos electronics restoration.
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Re: ABS Issue

Postby CDW6212R » Fri Sep 09, 2016 11:35 pm

Chris is very helpful with his fluent access to shop diagnostics, which is where your schematics came from for the relay. The diagnostic procedure is the best method, and for those of us who try with guess and replace, the last resort.

I wish I had the organization and motivation to do things that way, props to Chris, I appreciate his posts.

The ABS pump is very reliable, I would do ask suggested and check all of the wiring, grounds are another great thing to check. The pump generally won't die unless it's been forced to run too often(bad accumulator), or filthy fluid kills it.
Don
1991 Red Special Edition, my 2nd SE, dead paint, DWS 255/45/17's on 95 Cobra wheels, and soon; DVD/Navi/backup camera, OBDII and the 347, before custom paint.
98 Mountaineer with Continental DWS 255/55/18's, big sway bars, custom brakes. Soon to be A4WD with XP8 bumpers and wing.

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Re: ABS Issue

Postby autotraveler » Sat Sep 10, 2016 5:47 pm

Why can't I view the files attached to the post by WHITEOXLSC on Fri Sep 09, 2016 at 5:16 pm?

I'm properly logged in as I can post this reply. WHITEOXLSC, can you email me the file(s) to richtruesdell at gmail dot com?

I'm finding it really hard to believe that the pump just failed after replacing the relay, then driving the car 200 miles to have it fail again, then by jumping it, was able to drive 250 miles home, that the next day, after having the tires replaced, that it fails again and now can not be powered up by jumping the 3 and 4 terminals on the relay socket.

I'm now thinking that it can be a ground issue or, alternatively, that in pulling the relay out of the socket, I might have damaged the socket, specifically the 12v wire running from the socket to the pump. Now I will need to see if there is actually 12v going into the pump motor, at the motor. I will test that next along with the ground wire from the battery. Certainly a ground could be an issue. I certainly hope that the pump hasn't actually failed or burnt itself out.
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Re: ABS Issue

Postby CDW6212R » Sat Sep 10, 2016 10:35 pm

autotraveler wrote:Why can't I view the files attached to the post by WHITEOXLSC on Fri Sep 09, 2016 at 5:16 pm?

I'm properly logged in as I can post this reply. WHITEOXLSC, can you email me the file(s) to richtruesdell at gmail dot com?

I'm finding it really hard to believe that the pump just failed after replacing the relay, then driving the car 200 miles to have it fail again, then by jumping it, was able to drive 250 miles home, that the next day, after having the tires replaced, that it fails again and now can not be powered up by jumping the 3 and 4 terminals on the relay socket.

I'm now thinking that it can be a ground issue or, alternatively, that in pulling the relay out of the socket, I might have damaged the socket, specifically the 12v wire running from the socket to the pump. Now I will need to see if there is actually 12v going into the pump motor, at the motor. I will test that next along with the ground wire from the battery. Certainly a ground could be an issue. I certainly hope that the pump hasn't actually failed or burnt itself out.



I'm not sure which file you mean you cannot see, but Bob's last post was at 8:16PM Friday that I see, and there is one attached picture. The picture is showing the air spring compressor area, where the main ground connector is for the PCM and other critical items, maybe the ABS pump too. I can post a similar picture to show that ground connection. The battery ground goes to the radiator support bolt(check that well), and then it leads to the two wire ground connector near the starter relay, battery, and air compressor.
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Don
1991 Red Special Edition, my 2nd SE, dead paint, DWS 255/45/17's on 95 Cobra wheels, and soon; DVD/Navi/backup camera, OBDII and the 347, before custom paint.
98 Mountaineer with Continental DWS 255/55/18's, big sway bars, custom brakes. Soon to be A4WD with XP8 bumpers and wing.

ImageImage
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Re: ABS Issue

Postby WHITEOXLSC » Sun Sep 11, 2016 2:28 pm

CDW6212R wrote:
autotraveler wrote:Why can't I view the files attached to the post by WHITEOXLSC on Fri Sep 09, 2016 at 5:16 pm?

I'm properly logged in as I can post this reply. WHITEOXLSC, can you email me the file(s) to richtruesdell at gmail dot com?

I'm finding it really hard to believe that the pump just failed after replacing the relay, then driving the car 200 miles to have it fail again, then by jumping it, was able to drive 250 miles home, that the next day, after having the tires replaced, that it fails again and now can not be powered up by jumping the 3 and 4 terminals on the relay socket.

I'm now thinking that it can be a ground issue or, alternatively, that in pulling the relay out of the socket, I might have damaged the socket, specifically the 12v wire running from the socket to the pump. Now I will need to see if there is actually 12v going into the pump motor, at the motor. I will test that next along with the ground wire from the battery. Certainly a ground could be an issue. I certainly hope that the pump hasn't actually failed or burnt itself out.



I'm not sure which file you mean you cannot see, but Bob's last post was at 8:16PM Friday that I see, and there is one attached picture. The picture is showing the air spring compressor area, where the main ground connector is for the PCM and other critical items, maybe the ABS pump too. I can post a similar picture to show that ground connection. The battery ground goes to the radiator support bolt(check that well), and then it leads to the two wire ground connector near the starter relay, battery, and air compressor.
Image


Like noted above, pump failure could happen, but an electrical issue is more likely. According to the wiring diagram, the ABS main grounding does go through that connector(c103). CDW, your picture is better anyways, as it shows the complete wires from the negative battery terminal to the connector in question....BTW it's Bruce not Bob :lol:
Bruce
WHITEOXLSC
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1990 Regatta Blue LSC (newest addition aka Blu)
1986 Mark VII Silver LSC (sold, aka the Grey Ghost)
1990 Mark VII Oxford White LSC (new addition aka the WhiteOx)
1993 Ford Green Explorer Sport 2WD 4.0L V6 (daily driver do everything truck)(loaded first generation)
1988 Ford Blue/mostly rust brown Ranger 2.9L V6 STX P/U (Old faithful) (dead trans, 358XXX miles, sold)
1975 Oldsmobile Blue Omega Hatchback Coupe

Proudly supporting ; Pick N Pull of the greater bay area, NAPA auto parts, Ebay, Suncore Industries, Johnny Franklin mufflers, and Paul Protos electronics restoration.
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Re: ABS Issue

Postby CDW6212R » Sun Sep 11, 2016 9:59 pm

Sorry Bruce, I seem to say something different than I'm thinking, more often. My fingers do that too. I'm not sure how old I am, but it's enough I don't want to know.
Don
1991 Red Special Edition, my 2nd SE, dead paint, DWS 255/45/17's on 95 Cobra wheels, and soon; DVD/Navi/backup camera, OBDII and the 347, before custom paint.
98 Mountaineer with Continental DWS 255/55/18's, big sway bars, custom brakes. Soon to be A4WD with XP8 bumpers and wing.

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Re: ABS Issue

Postby WHITEOXLSC » Sun Sep 11, 2016 10:46 pm

CDW6212R wrote:Sorry Bruce, I seem to say something different than I'm thinking, more often. My fingers do that too. I'm not sure how old I am, but it's enough I don't want to know.


No worries my friend, I know we ain't getting any younger and it really doesn't matter who we are, as long as we help our fellow Mark VII owners keep there cars on the road..... 8-)
Bruce
WHITEOXLSC
ImageImageImageImage

1990 Regatta Blue LSC (newest addition aka Blu)
1986 Mark VII Silver LSC (sold, aka the Grey Ghost)
1990 Mark VII Oxford White LSC (new addition aka the WhiteOx)
1993 Ford Green Explorer Sport 2WD 4.0L V6 (daily driver do everything truck)(loaded first generation)
1988 Ford Blue/mostly rust brown Ranger 2.9L V6 STX P/U (Old faithful) (dead trans, 358XXX miles, sold)
1975 Oldsmobile Blue Omega Hatchback Coupe

Proudly supporting ; Pick N Pull of the greater bay area, NAPA auto parts, Ebay, Suncore Industries, Johnny Franklin mufflers, and Paul Protos electronics restoration.
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Re: ABS Issue

Postby mertrax » Wed Sep 14, 2016 6:40 pm

New the site I have a 91 LSC that I purchased for $350. 6 years ago... best car I have ever owned... Thank you for the posts about ABS, they led me right to the failing brake fluid, and bad relay...
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