Sign in to follow this  
Ronnie

Interesting ABS malfunction.

Recommended Posts

I though I would pass this on in case anyone else runs into this.

Today my wife and I took our Reatta for a routine Sunday drive. After we had driven about 40 miles through the beautiful hills of Tennessee my ABS light came on and stayed on. No red brake warning light came on. When I tapped the brakes the IPC and the CRT started flashing on and off as long as my foot was on the brake pedal.

I pulled over on the side of the road, turned the engine off, and checked the relay on the firewall for a bad connection or something and looked over the brake system closely. I found nothing so I cranked up and continued on my way with the ABS light still shining. No more flashing IPC or CRT when I pressed the brake pedal. After I had driven another 20 or so miles I pressed the button to look at the gages and the voltage reading was jumping around from 12.2 volts to 14.5 volts erratically. I thought the alternator was going bad.

We drove about 10 more miles and stopped at McDonald's for a burger. When we came out the car started up just fine, went about 20 feet and died. Cranked back up and went another 50 feet and died. When I got under the hood and did some serious checking I found the battery cable a little loose. Tightened it up and ALL the problems disappeared.

I told this long winded story to point out how sensitive the Reatta ABS system is to voltage supply. A lot of the unsolved ABS problems that have been reported here may be due to poor connections, weak batteries and charging systems instead of defects in ABS parts. In the future when someone posts a question about the ABS light being on, maybe we should recommend testing for proper voltage to the ABS system before swapping parts to try to get it working again.

I would never have thought that the ABS light would come on and stay on when there was enough power being supplied to start the car. It may have been caused by the erratic voltage caused by the loose connection to the battery. I really don't know. Anyone else experienced a similar problem?

Edited by Ronnie (see edit history)

Share this post


Link to post
Share on other sites

Not the same problem but similar. Back in 1984 when my Fiero was a week old I noticed that the dash lights were flickering from normal to bright, I was about half a mile from home so I tried to drive home. Then I began to smell something burning, as I reached to shut off the engine it died as did all power. I coasted to the front of my house hit a bump and the lights came back on and I saw smoke coming from the center console. Car would crank but not start. Dealer towed it in and found a loose battery cable. It took out the ECM which lives in the center console and the stereo. All repaired under warranty, had to complain to district manager to get a loaner car, ECM had to be ordered and when dealer would not provide loaner. I said the car is not even a week old, why should I have to rent a car?

Share this post


Link to post
Share on other sites

Ronnie my battery connection was not good one day on the road and my side mirrors went nuts. I thought it was the switch but I tightened the battery cables and all problems solved. My buddies here in Kansas blamed it on too much BUD. Not a chance that happened

Booreatta

Share this post


Link to post
Share on other sites

Maybe that issue is mine as well. I am going to try this as when I ran the codes again to clear them after changing the relays per Barneys suggestion, I got different problem code #s

Share this post


Link to post
Share on other sites

On the subject of battery connections and weird Reatta behavior, it's worth pointing out that the cable itself has a tendency to corrode internally near the connection to the battery on the factory-original wire. My old '89 had this problem (dash would come and go along with sending the chime module into fits) cutting the cable back a couple inches to clean copper and re-connecting it with a new battery connector fixed it.

Share this post


Link to post
Share on other sites

This post and others like it are what make this a great Forum!

This info should be added to reatta.net/brakes and other sites providing Teves info.

Hope Tom Jenkins is reading this. Maybe someone can contact him, I no longer have his email?

Share this post


Link to post
Share on other sites

Low voltage (12V) DC systems mixed with age, weather elements, and vibration...........and you have a recipe for problems.

Add saltwater to the mix.......and we boat owners are even that much more aware of how challenging an electrical system can be.

I had a battery fail, by leaking acid through a crack in the battery's mounting terminal. The acid was corroding the battery cable's bolt, that screwed into the terminal. Voltage readings all showed good..........that problem took sooooo long to figure out.

Share this post


Link to post
Share on other sites

This is a well-known problem with the side terminal batteries and some GM vehicles, notably the trucks/SUVs. Maybe also Reattas? There is a real Devils Triangle between the battery, the cables, and the alternator. The story goes something like the following:

There is a lead washer in the POS battery connection hidden under the rubber hood that gets squished/flattened when you tighten the bolt. When this happens, the bolt can bottom out in some batteries and feel 'tight' - yet the cables are still a bit loose. Since there is then a lot of heat that builds up in the loose connection, the battery can start to melt/crack and acid can start to weep out onto the cables and wick up them. Once the acid starts corroding the cable, and the connection becomes intermittent, it can take out either/both the battery and alternator.

I had the above happen to my Suburban about 10 years ago. Replaced the cables, and of course replaced the battery. There was acid mess everywhere too - so I went to an Optima AGM battery that will not leak. Of course the alternator went out a couple years later. No idea if it had been weakened by the bad connection or not. But I took the opportunity to upgrade to a CS-144, like our Reattas have, at the same time. No problems since then.

I don't know how the cables are set up in the Reatta yet. (Like, is there a squishable lead washer hidden in there?) But loose cables, leaking acid, and their aftereffects, are certainly something to watch for.

Share this post


Link to post
Share on other sites

It is called BEAT THE CLOCK,the pro"s use the air tools for everything.Installing battery terminals are there special.This will damage the battery and will take the slow way of distroying the cables with acid leaking. The battery, leaking bolt connection will need to be replaced.

Share this post


Link to post
Share on other sites
Guest Telco

Excellent, thanks for posting this up. I've been about to start chasing a number of gremlins in my car, but noticed that when I try to do things like raise the one working window when the engine is off that it goes about 1/3 the speed as when the car is running. I think I'll pick up a new battery for it first, then chase whatever's left over.

Share this post


Link to post
Share on other sites
Excellent, thanks for posting this up. I've been about to start chasing a number of gremlins in my car, but noticed that when I try to do things like raise the one working window when the engine is off that it goes about 1/3 the speed as when the car is running. I think I'll pick up a new battery for it first, then chase whatever's left over.

The slow window could be caused by a weak battery, however there is a better chance that you have a connection that has high resistance when put under a load, such as a battery terminal as described above. You might want to have the battery load tested before you replace it.

Share this post


Link to post
Share on other sites

AND-pry the terminal ends apart. They are like several washers , stacked. Corrosion gets in between the parts!

I had a battery that checked O.K. on 2 testers. Had the car towed to Buick. Anaylsis, a bad battery. Car would start, run about 10 feet then all went blank, engine stopped.

Share this post


Link to post
Share on other sites

When I bought my 91 convertible it would not run. The car looked nice but needed a GOOD jump start to run. Once running it would quit when driven 10 feet. Bought it anyway. Had it flatbedded to my mechanics shop. Repair order read "just bought car...doesnt run... make it run." Risky you say? Not really. Too bad NEMO cant find a competent, honest shop like this. They called me at 4:30 PM same day and told me that the car's battery had an internal short. They replaced the battery and it has run fine without a problem since.

Share this post


Link to post
Share on other sites

MY WORDS ARE TO MAKE ALL THAT SEE THEM WHAT DOES HAPPEN! You can live in the NO PROBLEM answer and see what you get. When you get the rush job so the Pro can make 10 hours pay before lunch.

Share this post


Link to post
Share on other sites
This is a well-known problem with the side terminal batteries and some GM vehicles, notably the trucks/SUVs. Maybe also Reattas? There is a real Devils Triangle between the battery, the cables, and the alternator. The story goes something like the following:

There is a lead washer in the POS battery connection hidden under the rubber hood that gets squished/flattened when you tighten the bolt. When this happens, the bolt can bottom out in some batteries and feel 'tight' - yet the cables are still a bit loose....

Thanks for bringing that to my attention. That was exactly what was going on with my loose cable connection. Although the bolt was tight the connection was still loose between the battery and the lead washer inside the cable.

I removed the bolt from the cable and installed a copper washer under it. That allowed the bolt to tighten down on the lead washer and cured the loose connection problem.

I highly recommend that other Reatta owners should check this. It could be causing a lot of intermittent problems that can't be otherwise explained.

Share this post


Link to post
Share on other sites

Hi Ronnie. It is good to know that this can be a problem in our Reattas. You might want to try using brass washers instead of copper. Less chance of corrosion.

Share this post


Link to post
Share on other sites

I suspect that the problem was not low voltage but rather spikes and no electronics likes that.

What happens with a loose connection is that it makes and the alternator starts charging. You hit a jolt, the connection breaks momentarily, and the voltage goes through the roof (ELI the ICE man).

In experiments with a 55 amp 10SI at DR I saw over 200V spikes when a loaded alternator had the load removed suddenly. I doubt that the dash voltmeter could follow a millisecond spike completely.

Share this post


Link to post
Share on other sites

I recently installed a new battery and had the same "bolt is tight but the cable doesn't feel tight" situation. Thanks for posting, I now know what to do to remedy that future headache!

Share this post


Link to post
Share on other sites
I suspect that the problem was not low voltage but rather spikes and no electronics likes that.

What happens with a loose connection is that it makes and the alternator starts charging. You hit a jolt, the connection breaks momentarily, and the voltage goes through the roof (ELI the ICE man).

Exactly. Even if the loose connection is tight enough that it isn't obviously intermittent, it still presents a higher resistance connection. With 10s of amps going through there, extra heat is generated. So one mode of failure is that the extra heat starts to melt/warp the side of the battery case around the metal terminal - allowing acid to seep out. This has devastating effects when it reaches the cable, as it can wick into it and cause hidden damage. Eventually this will get intermittent - just as if the connection was loose enough to 'rattle'.

The resulting "load dumping" can easily take out an alternator, and a bad alternator can take out a battery (and vice versa.) Witness Telcos recent post on how he always replaces both battery and alternator as a unit.

In experiments with a 55 amp 10SI at DR I saw over 200V spikes when a loaded alternator had the load removed suddenly. I doubt that the dash voltmeter could follow a millisecond spike completely.

Even if a dash voltmeter could follow it, the eye would not detect it.

I often wonder how many customers GM has lost due to this poorly thought out $0.10 washer.

Share this post


Link to post
Share on other sites

BTW the referenced study was done at Delco Remy in 1971-72 and resulted in SCCA kill switches having to chop the alternator as well as the battery. It is nothing new.

Share this post


Link to post
Share on other sites
Guest Telco

So this is a problem on the Reattas as well eh? It's also a big problem with the full size trucks, 1988 or newer at least. I replaced a "bad" starter because of this problem once, didn't discover it until the Delco starter "failed" again a few months after replacement and I asked about the problem on a different message board. The battery terminal felt tight every time too. That lead washer is removed on everything I get that has that stupid sealed positive terminal wire. A stainless washer will work as well, so does getting a bolt that's about an eighth of an inch or so shorter.

Share this post


Link to post
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

Loading...
Sign in to follow this