OK, like just about everyone else, I have the occasional ABS & brake lights come on. The local Advance Auto and Autozone cannot/will not read ABS codes for me. The codes come on and stay on until the ignition is turned off. then sometimes will stay out for some time.


I have checked my Factory Service Manual, and found several things that can cause the ignition latched codes. The common one is the solenoids in the module. I have taken this apart and re-soldered seemingly good connections. I have been involved with electronics manufacturing and design for many years so I know how to inspect them. I have also read the resistance of the 2 front wheel sensors at the control module connector and they read 0.99K and 1.01K ohms.


Sometimes the lights come on immediately after starting the engine, before I have moved an inch. Other times, they come on after driving a bit. It is unpredictable. The fact that it sometimes comes on before moving or even putting the car into gear, eliminates the dirty VR wheel sensors/reluctors or the speed sensor from the body control module. Besides, dirty sensor/reluctor should flash the light and turn off, maybe flicker.


This leaves me back to the control module. Right?


I don't think that I resoldered the motor relay inside the module when I was in there. Should I go back in and check? Is there some other possible cause that meets all of this scenario?

 

It sounds like you have the talent and ability to rewire the entire abs system. That would not be my first choice for solving the problem. The fault code will tell you exactly what circuit is triggering the light. There may be a repair shop in your area that offers free diagnosis or at least a scan. Or just show up to one with a cold 6-pack and ask why your abs light is on. I bet you'll leave with a code and no 6-pack. That's how I got my airbag codes. They even printed me a schematic.

 

on the drivers side, next to the radiator is a ground wire that is for the abs module. Try pulling it off and cleaning it. Worked for me

 

I;ve tried this and it didn't work for me. Replaced the control module too and still didn't help.


But like OP said, some days I won't get it all and others come on right after I start it up...

 

I checked the ground at the radiator panel and it no change.


Does anyone know, must the lights be "on" in order to read the ABS fault codes? i.e. can they be read as pending codes or in history even if the light is off at the time I get to the mechanic?

 

yes can be read as history

 

Did you replace the module with a new one or was it used if used or not replaced at all try this Google Search Chevy ABS AND BRAKE DASH LIGHT fix-YouTube.And then watch the video shows you how to fix it yourself.
It worked for me.Did you go on line and google this fix the solder points don't show they need soldering but once you follow the video if the solder points are the problem this will resolve P/S the ignition does have to be on to read trouble codes.

 

Thanks, but in my first post, I covered that.
Guess I'll try to find someone to read my codes stored in history.

 

My ABS problem was the wire harness from the under hood fuse panel to the firewall. It runs along the wheel well and was shorted, burnt, and corroded where it touches the bracket for the ABS motor. Looking at it costs time and effort, but no money. Pay extra attention to the larger red and black wires from the connector to the ABS motor.

 

I too am on this list; ABS and Brake lights come on sometime but only after driving a short distance.
I have cleaned the ground connection; but that was not it.
I will check the wire harness next and connectors next before taking the module apart and resolved connections. I need to find a shop that can read the codes.
I doubt it is the front ABS sensors as I replaced both last year when I put nee bearings in.
Wonder if the rear sensor?
Will check that as well,... really need to get the code.

Later