Adjudication by the ASA found the Mercedes-Benz ad was misleadingâ€š on two counts and must not appear in its current form again.
APA founding member Imperial Automotive Ltd objected to the implicit suggestion in the ad that body panels â€“ for example, a vehicleâ€™s front wings â€“ fulfill a safety function in the event of an accident.
Imperial argued that research refutes this, including the Autopolis Report, which judged many vehicle panels to be purely cosmetic.
Imperial also complained that the adâ€™s assertion that fitting any part other than a genuineâ€š Mercedes-Benz part could be a specific breach of legislation.
The APA was formed by Imperial (former name SEL-Imperial) in February.
APA chairman and Imperial boss Kevin Shipton, said: â€œThe advert by Mercedes-Benz epitomizes how vehicle manufacturers have been trying to persuade repairers not to buy non-safety critical replica crash repair panels.
â€œAs far as we are aware, there is no independent evidence to even suggest aftermarket replica parts such as front wings are different in quality to genuineâ€š equivalents.
â€œAftermarket crash repair panels represent good value for repairers and consumers, and we stand by the claim made by our membersâ€š suppliersâ€š that they match those supplied by OE manufacturers.â€