FAQ: Anti-Lock Brakes and/or Traction Control Light/Lamp On

AA wrote:

My guess is would be if you've replaced 3 of the 4 hubs, and that didn't fix it, might want to replace the 4th one. It's also possible that they told you the wrong hub................... -

You may just want to go back to Midas and have them scan with the super-duper again. That's what I would do.

As I mentioned in the first post;

I did go back to Midas. My friend the manager said it was the left rear twice on my initial visit,...I later replaced the left rear and went back to Midas. He cleared the codes and checked to see that they did not come back. There are no current codes.

albertj wrote:

The traction control pumps freeze up if the brake fluid gets too wet.
I don't remember anyone else posting about an EBCM going bad. IIRC it's on the firewall in the engine compartment and plainly marked with I think an "Ate" tag.

Albertj

Thanks Albert. Was that your thread with the coroded selonoid bank under the ABS pump?

I flushed all the brake fluid when I bought the car a few weeks back. I used Valvoline Syntec,...which is supposedly less hygroscopic than other Dot 4 fluids. (I use it on all my street cars that don"t see track duty). It used to be much better that the others and came in a gold bottle. They cheapened it up 6 months ago and now it comes in a white bottle with a blue label.

The old fluid was fairly dark (but I've seen worse),..and the bleaders all came loose failry easilly. I'm hoping the ABS pump[ and selonoid bank is OK.


I was at the junk yard today before you posted your answer, and I grabbed a brainbox behind the dash next to the ECU hoping it was for the brakes. I paid $8 for it. I figure if it wasn't what i needed i could just toss it.

Turns out what I bought was the digital climate control module. I just found one on Ebay for $250.00

Oh well,...I can go back.

duckstu wrote:

albertj wrote:

The traction control pumps freeze up if the brake fluid gets too wet.
I don't remember anyone else posting about an EBCM going bad. IIRC it's on the firewall in the engine compartment and plainly marked with I think an "Ate" tag.

Albertj

Thanks Albert. Was that your thread with the coroded selonoid bank under the ABS pump?

I flushed all the brake fluid when I bought the car a few weeks back. I used Valvoline Syntec,...which is supposedly less hygroscopic than other Dot 4 fluids. (I use it on all my street cars that don"t see track duty). It used to be much better that the others and came in a gold bottle. They cheapened it up 6 months ago and now it comes in a white bottle with a blue label.

The old fluid was fairly dark (but I've seen worse),..and the bleaders all came loose failry easilly. I'm hoping the ABS pump[ and selonoid bank is OK.


I was at the junk yard today before you posted your answer, and I grabbed a brainbox behind the dash next to the ECU hoping it was for the brakes. I paid $8 for it. I figure if it wasn't what i needed i could just toss it.

Turns out what I bought was the digital climate control module. I just found one on Ebay for $250.00

Oh well,...I can go back.

No, not my thread. I contribute to many threads, have only started a handful. I can explain many things because of personal experience or info learned from talking to mechanics at tle local Buick dealership. I like the guys, generally. And I will ask them what was the biggest headache or funniest thing they had to deal with this week or this month or since I saw them last or whatever. Learn a lot that way.

Did you look under the hood near the radiator overflow bottle for the EBCM?

Yep, I used to use Valvoline synthetic brake fluid, now I use Prestone synthetic, get it at autozone. By the way since you are hunting threads some time back I posted a how-to on building a brake bleeder from a garden sprayer. You might find it interesting reading.

Albertj

Well it came after i had done works to it. maybe after replaclign the front bearing but not so sure.
anyways.
Sometimes the TC goes off by itself. and then comes back on.
abs light dos not light on. but i know abs is working. so it cant b a speed sensor cos then abs would be on then.
any ideas?

Snowdog wrote:

Well it came after i had done works to it. maybe after replaclign the front bearing but not so sure.
anyways.
Sometimes the TC goes off by itself. and then comes back on.
abs light dos not light on. but i know abs is working. so it cant b a speed sensor cos then abs would be on then.
any ideas?

Check the TC switch, maybe get a replacement.

That is, next time you have the dash apart, use an ohmmeter on the switch. Disconnect it from the car, put the meter across the contacts and tap/wiggle switch. Does the meter show current if you just wiggle/jar the switch?

Albertj

deekster_caddy wrote:

traction control sucks doggie butt in the snow. I turn it off all the time in the winter. But there's a nice 'off' button right there on the dash. I like it in the rain, helps me get going quicker when I am trying to pull through a busy intersection.

I'm definitely going to have to remember to turn mine off before taking off. It won't let me go anywhere basically even trying to get out of the driveway. Not to mention it literally sounds scary when it engages. Almost like a creaking groaning noise coming from the transmission. Is that normal? Does having traction control engage hurt anything? It sounds painful

It doesn't hurt anything besides a little extra brake wear. Otherwise it's just applying the brakes and reducing engine power.

deekster_caddy wrote:

It doesn't hurt anything besides a little extra brake wear. Otherwise it's just applying the brakes and reducing engine power.

It sure does sound scary. Wouldn't happen to know exactly how it goes about reducing engine power? It sounds like when it does it the transmission groans or something.

Traction control works to reduce engine power by retarding or suppressing ignition spark, and reducing fuel supply to one or more cylinders.

ABS only activates the brakes - it does not cut engine power, as far as I know.

AA wrote:

Traction control works to reduce engine power by retarding or suppressing ignition spark, and reducing fuel supply to one or more cylinders.

ABS only activates the brakes - it does not cut engine power, as far as I know.

Interesting. It almost sounds like the groan is coming from the transmission when it engages. Be interesting to find out exactly what components are affected when the traction kicks on.

On a side note, is it normal for the ABS kicking in to cause the lights to dim? If so what causes it. Is it electrically assisted or is it hydraulically assisted ABS?

I do not recall lights dimming. Maybe you have a loose wire or bad connection on one of your major cables?

The groaning sound IS the ABS module, and it is near the transmission.

It is electrically actuated hydraulics... It's electrical solenoids pumping brake fluid to the calipers in little bursts, quickly. That's the 'buzzing' or groaning sound.

.....Also the hydraulic pressure is generated by an electrical pump that could be the reason for the lamps dimming they draw a lot of current.

Also they actually only release the brake pressure and then reapply while breaking.

Nigel

Oh and my ABS light went out this morning probably due to the tempreature 16 degrees!! which probably means a poor joint some where in the wireing.

The electrical pump makes sense. When the ABS kicks on it our Suburban it does the same thing with the lights dimming. I was just curious as to why it happens.

Is there any way anyone knows of to read the ABS codes through the climate control? My 95 roadmaster has a diag mode you can put its digital climate control into to read codes.

moldymac wrote:

Is there any way anyone knows of to read the ABS codes through the climate control? My 95 roadmaster has a diag mode you can put its digital climate control into to read codes.

Can not do that on the '95 & later Riv.

Albertj

When I got my 96' Riv, the ABS/Traction light was on. Luckily my buddy runs an auto parts store and a commercial account had returned a Genisys scan tool. Took all of a minute. Ended up being the harness to the front left wheel sensor.

It requires a dedicated scan tool, not a code reader. There is no code reader than can pull the ABS codes on these cars. The cheapest setup I found was a used SnapOn MT2500 with the updated ABS cartridge for something like $650 on Ebay. You won't find a new scan tool capable of doing it on these cars for under $750. I pretty much contacted every scan tool manufacturer out there during my search. That includes all the homebrew guys selling units on Ebay.

Thats too bad, I had a friend who owned one of the Actron brand ABS tools, and the riv was not supported. I replaced my front left wheel bearing because it started vibrating and that was unfortunatly not the problem. The dealer by me wants $109 just to scan it, and I called a couple small shops. but they didn't have a way of scanning the riv.

Yeah, I was going to just pay to have it scanned. I lucked out.

Hi,

Can any one tell me if i swap my 95 ECU for the same part number ECU do i have to do anything special to "calibrate" the new ECU to the new engine?

The reason im swapping is to get rid of the ABS code 77 traction lamp. I have replaced the ABS pump and solenoids to get rid of the ABS lamp but the traction lamp is stil lit. It is supposed to have 3 or some such volts on the pin going into the ABS computer, mine is at 9 volts!!!... hope the ECU sorts it...

Nigel

DTC 77 again? That's the delivered torque circuit (CKT 464, Tan w/black stripe).
Are you referring to PCM harness connector pin A14? From that pin to ground you SHOULD have approx 10 volts.
If you reconnect the harness and backprobe it, you should have approx 1 volt.

Not so much again but it never was cleared with the ABS pump/computer replacement. I guess its time for a few more voltage measurements.

Thanks

(tan w/black stripe). Check it for a short to ground and a short to voltage. Also, when you check it for resistance, move the harness around with the meter hooked to see if the value changes at all (frayed or corroded wire). J39200 is nothing but a multi-meter

If the ABS situation has been corrected, the light should go out on its own. At least OBDII works that way. Maybe you haven't solved the problem?

Funny thing happened tonight. A few months ago I bought a used set of 18" rims w/tires mounted, and finally got around to installing (two of) them this evening. I was told by the seller they might be a little out of balance, so I tried two on the front to see if I could feel any vibration at speed.

Also, the tires mounted on the rims are 215-45R18, a 3.7% smaller overall diameter than my current 225-60R16 on OEM 16" rims. I wanted to see how they looked installed on the front before installing the rears - if they look stupid, I'd just wait and buy the correct tire size.

So I installed just the two fronts and then headed out. Car drove fine around town, so I headed out to the highway. Got on a ramp and brought the car up to speed. Everything was fine for about 30 secs at 70-75 mph, and then something very strange happened. The car started to slow down. I gave it more gas, and it fought me even more to slow down. I thought the transmission might be slipping, but something else was going on, because I was having trouble keeping RPMs up. It was almost acting like I was out of gas!

I got off at the next ramp and noticed my power returned, car drove just like it's supposed to. That was good news, but I wanted to know why we had that incident on the highway, so I got back on and took her up to speed again - same exact thing happened. Lost power, then I slowed down and it came back. It's the weirdest thing I've ever experienced in this car. I tried it a third time, same result. I was perplexed for a few minutes... then it hit me.

Turned traction control off, went back out on the highway, problem solved. Drives like a dream again!

So I guess that 3.7% difference in tire size is enough to convince the TC system that I'm spinning out the front tires. If you do the math, we're talking about a 2 MPH difference at 60 MPH. So the computer sees 60 MPH at the rear wheels, and 62 MPH at the front, and then all hell breaks loose. I just didn't think that small of a difference would be significant. Oh well, live and learn.

Anyone thinking of making their back tires even a small amount larger than the fronts, remember to turn off TC every time you turn the key!

Very Interesting. I don't think I would have thought about TC being the problem for a while.
Maybe quite a while.