P0A0A High Voltage System Interlock Circuit A. This is the code that completed our year 2023 and was repaired when we returned in 2024. Is there anything special about this code? Certainly, hence the reason for this article!
So, let’s start with the information in hand. A 2014 Ford Focus Electric arriving from another workshop. The vehicle does not enter “Ready” mode. Analyzer in hand, we read the data to find the code mentioned above. So let’s read the diagnostic charter, and see where it takes us.
Step one, we’re asked to do a code reading to confirm that it’s present, and it is. Step two, inspect the high-voltage connectors on both high-voltage batteries, the one inside the rear trunk, and the other under the vehicle.
Interlock circuit health
A quick glance isn’t conclusive enough to say there’s a problem. Step 3, we disconnect the high-voltage connectors of the high-voltage battery inside the vehicle to be able to measure its interlock circuit.
It passes the test, so we can now conclude that the problem probably lies in the other high-voltage battery.
Step 4, the same measurement performed on the battery in the rear trunk is repeated. And this is where we find our problem.
Disconnecting one of the connectors on the battery reveals the corrosion that causes the problem. At this point, the charter asks us to repair the connection, which unfortunately is part of the battery that should be replaced.
Is this the repair we made? Certainly not! A little research at an independent connector supplier helped us find the same ones, which we were able to replace to get this little Focus back on the road again.
Cost-effective repairs
Complete repair, at a more than reasonable price compared to what the customer would have paid the dealer. The special feature of this EV is that no information is readily available on the components inside the high-voltage batteries. Pourquoi? For this specific model, we have to believe that Ford has no solution for internal repairs, so when we fall inside the battery, we have to go with our acquired knowledge.
The year 2024 is off to a good start, and I hope it’s the same in your workshops!
