Nissan: MIL On With Code P0603 Stored For ECM Back Up Circuit
Step 1: Confirm that the battery voltage is 11 volts or more, with the ignition on and engine off.
MINI Power Loss, Multiple Diagnostic Trouble Codes
The customer says the MINI Cooper loses power between 30 and 40 mph for a couple of seconds, with other components also powering down. The A/C blower will drop, and after the engine picks back up, the MIL illuminates.