1997 GMC Safari

Engine Size : 4.3 Vortec
Hi, After a long trip, I pulled into a parking space and went to back out and reverse didn't work, I have to pull in where I can only go forward now. Someone said a

1998 Chevy Asrto van.

Engine size- 4.3L Vortec.
Warning lights: just the ABS
Computer codes: EGR valve code

1996 Chevy Astro 4.3 Vortec V6.

Rear brake line replacement done by unknown shop.
Master cylinder and wheel cylinder replacement.
Rear brakes are inop. was told by repair shop that ABS pump assembly needed to be replaced.