My 99 Cavalier ABS has had this fault going for a year. I have tried to track it down but with no luck. I even had it at a dealer and they could not pin it down even with their Tech 2.

The symptoms are: If the vehicle sits for a day without running and is then started, the fault lights will be out and all will appear normal. As soon as a put the car in gear and then roll about 10-20 feet, I will hear a "crunchy" sound up under the hood on the drivers side (most likely the ABS pump motors moving) and then the lights will fault on. They then stay on throughout the driving cycle and will stay on for successive restarts unless the car gets at least a good 8 hours or so to sit.

While I had it at the dealer, I had the brake system completely flushed out and bleed out with fresh new brake fluid - it was overdue for that in the hopes that the Tech 2 motor assist bleed would exercise the motors and clear out any possible issue. After doing all of this the dealership still had the fault and indicated that the problem was with my ECBM located inside up under the dash near where the hood release latch is in the interior. So I swapped my ECBM box between my 1998 and my 1999 and waited a day to see if this was the case. I started up the 99 the next day and got the normal no light followed by the usual under the hood ABS pump sound and then the lights after I rolled the usual distance down my driveway. No joy there. This tells me it is not the ECBM.

Since this initially registers as normal but then activates the faults after motion, I am wondering if it is the indicator strobe ring on one of my CV joints. When I last inspected them when I check the sensors they appeared more or less normal and I brightened them up with a wire brush. I read about cracks sometimes in these in another older post and plan to check for them when the weather gets warmer but in the meantime am very interested in anyone else's thoughts from here - that is if it is not too much of a ghost town here as seems to be more and more the case these days.

thanks,

Brian

Did you successfully resolve this issue?
I have the same issue with my 1999 Sunfire GT.

I sure wish I did but nope, I still have the issue. I even had the dealer try swapping the entire master cylinder brake pump for another one in near new condition and they could not find the problem. Waste of time and $. When cold weather returns, it will no doubt take up where it left off in March and resume teasing me again by going out only to com back on after rolling a few feet and making that ABS pump motor "crucnchy" noise that it does. I may try a different dealer when I run into something that I cannot fix myself the next time. I have 2 spare master cylinder brake pump assemblies handy to try out. Other than this the car continues to run great.

Does your Sunfire play mind games and temporarily "recover" and have the lights go out when it is cold like mine does?

Brian

In a nice change up from the most unwelcome spam of the last 2 weeks or so (cough-cough!) here is something J-body related.

Cold weather is now here and thus as predicted, the ABS and the brake cluster lights in my 99 cav have begun their seasonal "teasing".

It's the same old same old:

1. Cav starts up and the lights are out (could it be?...)
2. Cav rolls forward a few feet
3. I hear the "crunchy" sound of the ABS pump doing whatever it does from under the hood
4. The ABS and the red brake instrument cluster lights come back on (Nope.)

One of these years I suppose I will figure it all out...

As prior, I am still wide open to troubleshooting tips and any comments to diagnose are welcome. As I mentioned above, one dealer has already attempted a fix but could not figure it out. It cost some $ trying too but they gave me a Sr. discount to make it sting less. (Up until that point in my life I had never gotten a Sr. discount before so in a way it still stung pretty bad)

Brian

Lots of youtube videos about this.
Search for ABS faults.
Could be wheel bearings or bad wheel sensors, even just magnetic filings on the sensor faces.

Good suggestions and I tried all of that except for changing out the bearings and am deliberately not touching them since they are all quiet.

2 years after posting this problem is still persisting for me. I even had a dealership scan for it with the old tech unit but they could not figure it out nor seemed to want to try very hard since it is a 99 has been Cavalier.

We had a couple of super cold days here about 2 months ago that were sufficiently cold enough to make the lights go out. Same old story, put the car in drive, let it roll about 10-20 feet at idle and then you hear the "crunchy" sound of the ABS pump unit activating under the hood and then the lights come on.

I actually made a movie of it showing the lights complete with sound and you can hear it al very well. I do not have a youtube account but maybe I can get my son who does have one to post it if anyone is interested.

99ln2

https://youtu.be/QZXLj37ZIfo?t=501
start there. Same pin out as a Cavalier.
Wiring to each wheel should be only a few ohms, the front sensors on mine measure 1,600 ohms more or less, and the rears about 1,000 ohms.
The wires to each wheel should be only a few ohms.

Insufficient signal to the ABS pump module will make it think a wheel is locking up.
Temperature changes can make for intermittent operation when things are on the edge of working.
I fixed mine by replacing the module, but the symptom was for no ABS operation at all, just the warning light.
New old stock on eBay for $179.

eBay item number:
143186452077