See list attachedSeptember 26, 196868-PA-T-208APA/Chief, Apollo Data Priority CoordinationUnusual procedure required for LM Ascent from the moon
Jack Craven surprised us with a little jewel the other day during the Lunar Surface Mission Techniques meeting. He says that in order to enable the APS engine-on and staging commands from the LGC, it is necessary for the crew to depress (now get this) the Abort-Stage button! That is, depressing this button must be part of the standard countdown procedure to LM liftoff.
Alternately the crew can manually arm the engine which permits them to send the engine-on command manually, but it does not enable the LGC signal. Furthermore, if they do this, it is necessary for the crew to also send the engine-cutoff signal manually since the signal from the LGC is inhibited.