We are running full stand alone with a E38 controller and 6l80E no BCM. No issues other than the battery will go dead after several days.
I have traced this down the the GM E38 ECU is staying awake all the time. If you plug a scanner in it will continue to read live data for days even after the key has been turned off. If you press that gas the pedal will read on the scanner coolant temp etc.... still live. Swapped different ECU's with same results
I have verified my battery and switched voltages.
X1-19 is switched 12volts
X1-20 is battery hot all the time
X1-47 is switched 12volts coming from the powertrain relay.
I can actually unplug X2 connector and loose some data that comes in on that plug but the ECU still stay awake and sending TPS data etc.... so i know its nothing on X2
The only other voltage on X1 is pin 61 EVAP VENT. I can unplug the vent valve and still have a issue so I know thats not it.
Im thinking the ECU is either staying awake to run some sort of emissions test or is waiting for a signal from the BCM to power down.
If its a BCM message that is is waiting for then why doesn't everybody with a E38 standalone have this issue, I have searched online everywhere and not one mention.
If its an emissions test that it want to run is there a way to disable it or change the timers so the ECU will power down?
If i remove the battery power from the ECU and plug it back in it will stay asleep until I cycle the key and then it will stay awake until the battery is dead.
Anybody have any insight?