I have a constant error that appears on the gauge cluster, this has been there ever since I bought my pre-owned 2012 manual Mustang GT.

I checked every single detail with regards to the car electrics and wiring internally and externally, the last procedure I did was I replaced my ECU entirely but the problem still presists.

I need your help and expertise, or if anyone whom has or had the same issue and what they did.

Thank you folks.
Nabz

 

Did you scan the ECU for codes?
Measure the voltage across the battery posts with the engine off and with the engine idling (no electrical accessories running), then tell us what you find.

 

that error is usually related to a failing alternator or bad ground that is tied to alternator or battery. As mentioned, check the voltage at idle and also check it at 2000 RPM. what do the numbers say? If that shows up okay, it can still be a bad alternator or ground. You can still get the required voltage but not not amperage.