Who is allowed to issue a certificate on the testing of a speed limiter?

You answered correctly. Only the vehicle manufacturer who is officially recognized and workshops that are authorized by an authority can issue a certificate on the testing of a speed limiter. Not all garage workshops for commercial vehicles are permitted to do this—specific authorization or recognition is required. This ensures that speed limiter testing is performed and certified according to regulated standards, providing safety and compliance with the law. In similar questions, look for answers that involve official recognition or authorization when it comes to legal certifications.