2005 Cadillac STS with the 3.6L LY7. It won't crank with the ignition switch. Some hack shop already sold the customer a starter and a battery. the engine will run if the ignition is "on" and the starter manually powered up. On this car, the instrument panel module is the power mode master and is responsible for waking up the other computers on the hi and lo speed GMLANs. The IPM is sending the wake up signal to the ECM, yet it still isn't communicating with the rest of the computers. Let's see what we can glean from the Tech 2...