I hate he word "Auto" correct as it changes the words I type. But yes, GM had passkey 1 & 2, the passlock, Immobilizer, Passlock 3, Passlock 3+ which is + with circle on it. But in the late 90's, Passlock on trucks was the first design. The RFID is in the head of the plastic key and communicates with the ignition switch ring/anti-theft lock module. Early ones generated a 5 volt constant voltage input to PCM. Next gen produces a predetermined frequency many a 20hz. This too was constant freuentcy that once the PCM received, had and "Electronic-Hand-Shake" then defaulted to an new strategy. If the vehicle is started, everything works normal. If the signal is lost or class2 network goes down while running, the engine stays running while turning on the theft light. Only once per cycle? No. It ignores the Passkey system all together and allows the vehicle to be started. The exact system the 1998 Suburban has on it, will be found on paper service manual. The electronic version of "Service Information" copied only engine and transmission for 97, 98 only, then went full blown electronic with all systems, accessories, body, electrical and diagnostic flow charts going forward. Hanyes of Chiltons are useless for exact vehicle systems. Mitchells and All-Data paid to copy certain pages of GM service information, but not all pages. Using these system in a shop or garage will find "Holes" in service information.
It is the same issue for software for SnapOn and others when it comes to access on systems. Body function take a hit and only "One" fail-records instead of all five fail records. A tech can go back in time with these fail record to see the same code set and certain temps, speed, RPM, TPS, MAP etc. This becomes helpful as after a fix, these perameters can be reproduced to see if the code returns, also check if code is pending, waiting for second failure when the test is run...only on type "B" codes, "C" codes and now "D" codes. "A" code types set the MIL/CEL on as soon as the code sets. Vehicle malfunctions are different from MIL/CEL as they will turning on Service Vehicle Soon" lamp.
I this I had these paper service manuals but do not and limited information is on the internet. ASE Master since 1978.