Options for resolving disputes regarding a kid on a 504 plan are different than they are for students on an IEP.  They’re not as efficient and speedy as options for resolving disputes concerning students on an IEP.  If there is a dispute involving a student on a 504 plan, school districts must conduct an impartial hearing when parents disagree with their child’s identification, evaluation or placement.  The details are left up to the discretion of the school district and hearing officer.  Parents often are unhappy with this option, so they may choose to file a complaint with OCR. This complaint may or may not be accepted by OCR, it will take several months for OCR to deal with it and OCR has limited enforcement mechanisms.  OCR will threaten to pull funding from a school district for violations, but this is extraordinarily unlikely.  
Still, OCR can help parents and districts mediate disputes.  Plus, the possibility of OCR consequences normally is enough to get districts to remedy their behavior in case OCR has determined that a district has engaged in a discriminatory fashion. What’s particularly frightening for districts is if a parent files suit in federal court under 42 USC 1983 (simply known as “1983”) and can prove discrimination against their 504-protected child.  If a parent wins such a suit, the damages could be substantial, and the district would have to pay the parents’ attorney fees, which easily could get in the tens or even hundreds of thousands in a federal case.