DTC P1693: DTC DETECTED IN COMPANION MODULE
Turn ignition on with engine off. Using scan tool, clear DTCs from PCM. Using scan tool, check for stored DTCs in ECM. Perform appropriate test procedure for stored DTCs in ECM. Perform TEST VER-2A .
This error code cannot exist by itself and will have other error codes present in the ECM and/or PCM you'll most likely require an OBDII scan tool to get the codes. P1693 is nothing more than a flag that is pointing to the other module stating there are errors. If the PCM has the P1693 code this only means that the error codes are on the ECM. Visa-Vera as well. If the ECM reports the P1693 that means the error codes exist on the PCM. If both report the P1693 code basically both module pointing the finger at each other stating there are errors on both modules. Typically the key trick is the only place this code will show up. I've also seen a few "cheap OBDII code readers" also report this code but doesn't state which module reported. Always best to use a quality OBDII code reader.