Is that the only code you're seeing? Have you done any mods lately? When I replaced my injectors, after reconnecting the high pressure fuel system and using the lift pump to bleed the system, the engine was hard to start and ran rough for a short time and I saw the check engine light come on. I then had the 1693 code only and no wait-to-start light. I disconnected the batteries, turned the ignition to on, waited what ended up being a couple of hours, then turned the ignition off, reconnected the batteries, and no more codes since. Also got my wait-to-start light back. Your other choice is to find a code reader (some say AutoZone will do it free). Good luck.