E09
Cadillac Internal DC Power Supply Fault

Charger shows E09; charging stops unexpectedly and cannot be restarted until power is cycled.

Advertisements

Safety Warning

This repair may involve working with high voltage components or water connections. Always unplug the appliance before removing any panels.

If you are not confident in your ability to perform this repair safely, we strongly recommend contacting a professional technician.

Advertisements

Possible Causes

Failed low-voltage power supply on control board, Surge damage from lightning or utility event, Loose low-voltage connectors between power board and logic board, Overloaded accessory circuit (Wi‑Fi, RFID, etc.)

How to Fix / Troubleshooting

Safety first: Turn OFF the breaker before touching the charger housing or opening any covers.

Steps to try:

  • Check for recent storms or surges: If E09 appeared after a lightning storm or power outage, the internal supply may have been damaged.
  • Power cycle: Turn the breaker OFF for 10 minutes to allow capacitors to discharge, then ON. Observe whether the charger boots normally and if E09 reappears.
  • Reduce accessories: If the charger has optional accessories (Wi‑Fi, load management modules), disable them via the app (if possible) and test again.

When to call a technician: E09 almost always requires internal repair. A technician should test the low-voltage rails and replace the control/power board assembly if the DC supply is unstable.

Advertisements

Repair Difficulty

Professional Required 5/5

Required Part

Cadillac EVSE Control/Power Board Assembly
Check Price on Amazon

We may earn a commission from links on this page.

Advertisements