ABS-light and strange sound

[Danish Farmer]

Hi gyes

On my Silverado, 1995, the ABS light has started to come on at some point every day, but disapear again after some minutes.
Brakes are working fine, but some times the pedal will feel hard and make a surring noise. Like it will not sink as deep as it use to, and kind of vibrates and feels hard to press enough to make a short stop.

Hub assemblyes in the front are only two months old, and pads and one caliber was changed at the same time.
Fluid-level is at MAX, and there is no connection between when the light is on, and when the pedal acts like described above.

What could be wrong ?

Regards,
The danish Silverado-owner

 

[ak diesel driver]

I believe the weird pedal is your ABS working. When the ABS turns it self on/off it will activate the ABS, at least that's what mine does. I have the same issue and need to replace my drivers side speed sensor

 

[Heartbeat Hauler]

Maybe a quick run to autozone and get it scanned to see if there are any codes that might point you in the right direction.

 

[Heartbeat Hauler]

Oops! I just saw you are in Denmark....sorry... Probably no autozones there...:skep:

 

[millsroger]

If you have the rear wheel ABS then this may help, not valid for the later "all wheel ABS".

The following is a list of the trouble codes for the Rear Wheel Anti-Lock (RWAL) brake system.
Code 1: Invalid code
Code 2: open isolation solenoid or EBCM malfunction
Code 3: open dump solenoid or EBCM malfunction
Code 4: grounded anti-lock pressure valve rest switch
Code 5: excessive dump valve actuations during anti-lock stop
Code 6: erratic speed signal
Code 7: shorted isolation solenoid or EBCM malfunction
Code 8: shorted dump solenoid or EBCM malfunction
Code 9: open or grounded speed signal circuit
Code 10: stop lamp switch circuit
Codes 11 and 12: invalid diagnostic trouble codes
Codes 13, 14 and 15: electric brake control module malfunction

READING CODES
The RWAL ECU will assign a code to the first fault found in the system. If there is more than 1 fault, only the first recognized code will be stored and transmitted.
Trouble codes may be read either though the use of TECH-1 or equivalent scan tool or by connecting a jumper wire from pin H on the ALDL to pin A. If the jumper method is used, the fault code will be displayed through the flashing of the BRAKE warning lamp on the dash. The terminals must be connected for about 20 seconds before the display begins. The display will begin with 1 long flash followed by shorter ones-count the long flash as part of the display.
Sometimes the first display sequence will be inaccurate or short; subsequent displays will be accurate.
If using a hand scanner, note that if a soft code is stored, only the last recognized code will be retained and displayed on the scanner. Soft fault codes 6, 9 and 10 can only be read with a scan tool. Codes 1, 11 and 12 will not read on the scan tool; they must be read using the jumper wire method.
Never ground terminal H of the ALDL to terminal A if the BRAKE warning lamp is not lit. Doing so will set a false code 9 and illuminate the BRAKE warning lamp. With the brake lamp on, the RWAL system will be disabled.

CLEARING CODES
Stored trouble codes must be cleared with the ignition switch OFF. Remove the STOP/HAZARD fuse for at least 5 seconds, the reinstall the fuse.

 

[Danish Farmer]

Thanks gyes

She´s only giving codes for the goofy EGR-system and no one for the brakes.
The other day when the pedal did the same trick again, it became hard like a rock, and would not stop the truck, before I released the pedal and pressed once again. Any other clues ?
Orange ABS light will coma on and off, but never the red one

Regards Max