How do you replace the ecm on the envoy?

To replace the ECM (Engine Control Module) on a GMC Envoy, first disconnect the battery to ensure safety. Locate the ECM, which is typically found in the engine compartment; remove any covers or components blocking access. Disconnect the wiring harness and unbolt the ECM from its mounting bracket, then replace it with the new unit. Finally, reconnect the wiring harness, secure everything back in place, and reconnect the battery.