abs INOP/brake light troubleshooting
 

I have a stock 96 z28 and ever since i've had the car, both abs inop and the brake indicator lights have been on. I have put new pads and rotors on front and rear but I still don't know what could be causing it. I have a Snap-On OBD scanner but it doesn't do abs codes. I've been told it could be my wheel speed sensor but i dont know if it would cause both likes. How could i test my wheel sensors?
Thanks for any available advice.

Re: abs INOP/brake light troubleshooting
 

Brake pads, rotor problems and low fluid in the master cylinder reservoir don't set ABS codes of turn on the lights.

The "BRAKE" light indicates there is a problem with high differential pressure in the front and rear brake hydraulic systems. Could indicate a leak in front or rear system, air in one of the systems, etc.

The "BRAKE" light is also turned on when certain ABS system codes are set, to identify a possible underlying problem with the basic braking system. The codes in the ABS system that turn on the "BRAKE" light are primarily related to failures in the ABS relay, failures of the three brake motors in the main ABS unit, and a failure of the electronic braking control module (EBCM). The ABS system does not turn on the "BRAKE" light for failures of the individual wheel sensors. At least that's what it shows in the 1996 factory service manual.

You can download a copy of the factory manual here (you may need to sign up for the site):

LINK: 4TH GEN SERVICE MANUALS

Best way to handle it is to find a shop that can read the ABS DTC codes, or there are relatively inexpensive aftermarket scanners that can work with the 1996 system.

In the meantime, might not hurt to inspect your brake lines and calipers, and check the level of the fluid in the master cylinder.

Re: abs INOP/brake light troubleshooting
 

Scan9495 will work for the 96 ABS. It will show trouble codes and reset them and a few variable parameters. It will not work for 96 engine and SIR.

Most OBD2 scanners will not work for 96-98 ABS because that is on the old OBD1 bus (separate pin in the connector)

Re: abs INOP/brake light troubleshooting
 

When was the last time the brake fluid was changed? It should be changed every 2 years.There is a test most brake shops do to check if the brake fluid is good or bad.Hope this helps.

Re: abs INOP/brake light troubleshooting
 

The abs and the third break light on on the same circuit .Might pull out the third brake light lens and check for bad connections(melting like my old bird).Other than than that, I'm at a loss.Most problems from previous posts have been from dirty sensors at the wheel.Hope this helps.my02.

Re: abs INOP/brake light troubleshooting
 

I know you said "stock" so does that include the stock wheels/tires? If not, then the overall diameter of wheels/tires can't have more than a 1" overall difference or that will also set off ABS light...

Re: abs INOP/brake light troubleshooting
 

Haven't heard from you for a while but I hope you fixed the problem.This is a long shot,but when I had the brake light switch replaced(it's under the dash on 93's)my problems were solved on the old formula I had.Hope this helps.:)