Here you go gang... I produced a in depth error code list for the 1998.5 to 2002 Dodge Cummins trucks this should help you troubleshoot most all problem that toss a error code or a check engine light. Mopar1973Man's Dodge Cummins Articles - 2nd Generation 24V Dodge Cummins - OBDII Error Code Listing I know a bunch of you use the ignition ket trick to read error codes but remember 98.5 and 99 don't have this function. Then 2000 will work for the most part. Then 2001 truck will only report just the PCM. Then 2002 works fine. So OBDII reader should be used to double check error codes. Another note... P1693 code can't exist by itself so if you only getting a P1693 code you should try using a OBDII code reader instead of the key trick method. As for erasing codes use a code reader and use its RESET/CLEAR CODE function. Disconnecting the batteries will not erase codes nor will it reset the computers (ECM /PCM). But it will wipe out the APPS sensor calibration. (Another writeup). The ECM/PCM can self erase a error code after 40 warmup cycles of the engine. Just because there is no CHECK ENGINE light doesn't mean there isn't any codes either. There is many of these error codes that will not trip a check engine light so the problem can lay there waiting for a long time.