STEP 1. Measure the voltage at the electric parking brake ECU connector.
(1) Disconnect the electric parking brake ECU connector and measure at the wiring harness side.
(2) Measure the voltage between the +B1 terminal and ground.OK: The voltage should measure approximately 12 volts (battery positive voltage).
Is the check result normal?
Go to Step 2. The power supply circuit may be open or short to ground. Repair the wiring harness wires or connectors between the electric parking brake ECU connector and the battery.