1996 Chevy ABS update:

Well had the codes scaned for my ABS light always on. I got the following: C0021, c0022, c0026,c0035, c0037.

He asked me if I had unpluged anythign and I told him I had at the module under the hood earlier in the week. He did some fidling with his scanner and said the codes came back again and that the unit either was bad, or there was a ground problem somewhere.

This is my daily driver but has 315,000 on it so I dont want to put alot of money in it. I do all of the work on it myself. Thing is, I think it needs a master cylinder. But, if the ABS cant be cylced to purge air, how can you do it? Elsewhere in this forum someone suggested a procedure which I am willing to try, but if I mess up and get somethign wrong and get air in the system I am not sure what I will be able to do.

1) Is it possible or even feasible to just , with new plumbing, bypass the ABS module. (Run lines directly from mast cylinder to brakes.

2) If this could possible be a ground, where do I look?

I will say maybe once every two months I get in it and the light stays off untill I get on the highway. My hopes go up thinking it fixed itself then it always comes back. 90% of th etime the light comes on as soon as the key is turned over.

I appreciate any help as I am at a loss.

I don't know about your specific ABS unit but I have seen problems with various electrical devices where they were grounded to the vehicle body and the negative battery cable is connected to the engine block and the connection between the engine and the body has deteriorated, so I would check where the ABS unit is grounded and then confirm, with a meter, that the path from the ground point to the battery negative terminal is essentially at "0" ohms resistance.

This may not fix it but at least it would let you eliminate one thing from the discrepancy list.

Bypassing the ABS is perhaps not the best thing to do as all cars have a greater braking capacity at the front then the rear as most of the braking is done with the front wheels. This brake balancing is done several ways. By larger or more powerful brakes on the front then the rear, or by a pressure reducing valve for the rear brakes. The ABS system may incorporate this function and you really do not want to eliminate this balance as it will cause the rear brakes to lock under normal braking conditions.

John B. Slocomb (johnbslocombatgmaildotcom)