Mustang Fault Memory Lock Active

I had a similar issue on my 2018 Audi A4. The error memory lock was triggered by undervoltage. Check the battery's health and charging system output. A weak battery or faulty alternator can cause it.

I did a preliminary check with a multimeter, and the resting voltage seemed okay, but I didn't do a load test. What steps did you take to diagnose the undervoltage in your Audi? Any fault codes?

The multimeter showed acceptable voltage, but the issue was only apparent under load. The fault codes were related to the ECU being unable to maintain sufficient voltage during operation. Given your Mustang's mileage and the 'fault memory lock active' error, I'd suggest a workshop visit for comprehensive diagnostics. They can do a proper load test and pinpoint the cause. It's the safest route.

I visited a certified Ford workshop. The issue was traced to undervoltage, needing a control unit reset. The repair cost 240€ and resolved the problem. Thanks for the help.