BMW i3 doesn't start or charge
The customer had driven the car to charge, but suddenly the charging stopped, and the vehicle was unable to start. A tow truck delivered the BMW i3 to our workshop, where the car was completely unresponsive. We pushed the car into the workshop, charged the 12V battery, and the car began to show signs of life. However, it was still unable to start, with several warnings, including a drivetrain fault.
High Voltage Battery faulty batteri defekt
We read the error codes, and it appeared that the high-voltage battery’s fuse was blown. We removed the 12V battery and let it charge. Then, we removed the high-voltage battery, opened it, and confirmed the diagnosis – the 350A fuse was blown. We replaced the fuse with a new one, performed a health check on all modules, and confirmed that the battery was in good health and condition. We reassembled the removed components, cleaned the battery, and sealed the top cover to prevent water ingress.
When we reinstalled the battery into the vehicle, we disconnected it, as the fuse blew for some unknown reason, and we didn’t want the new fuse to blow right away. We began to perform manual diagnostics and measurements to confirm which high-voltage component had short-circuited and caused the fuse to blow in the first place.
Drive inverter failure (EME)
After some insulation measurements, when we measured the drive inverter (EME), we heard a clicking sound (spark) inside the inverter. The resistance value was lower than expected. We removed the inverter and opened it for inspection, and discovered a hole in the bottom cover of the aluminum housing. The hole was caused by shorted electrical components in the inverter, as if someone had welded through the aluminum housing. We replaced the inverter, reassembled the vehicle, and reconnected both the high voltage battery and the 12V battery.
Voilà, the car started without any warning, shifted into D and R, and we confirmed that it ran without any problems. Happy days! However, there was one thing left to check before we delivered the car back to the customer – namely whether the car could charge. The car would not charge.
Charging Issue
When we opened the charging port, the white LED light lit up, and it was ready to receive the cable. When we connected the cable, it was supposed to start blinking blue, but no, it remained white, and the locking mechanism started making buzzing sounds. After a few seconds, the red LED light lit up and began blinking, and the “charging unavailable” warning appeared on the screen.
We performed diagnostics, inspected the charging cable and all cables from the charging port to the charger, and found no issues there. When we removed the charging port cover, we discovered that the locking mechanism had previously been worked on by someone else and glued with hot glue.
Since the mechanism contains a Hall Effect sensor, we measured the resistance at each movement of the locking mechanism and confirmed that the mechanism was incorrectly assembled. We assembled the mechanism and gears correctly to match the correct resistance values at each stage, assembled all other components in place, and tested the charging, confirming that the charging problem is resolved. The car was delivered back to the customer with extremely positive feedback.
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