The park lamp flash relay circuit is detecting a short to battery voltage, meaning the electrical path is sending too much power directly to ground instead of controlling the relay properly. Think of it like a water pipe that's cracked and leaking—the pressure goes where it shouldn't instead of flowing through the intended valve.

The ECU monitors the park lamp relay circuit voltage and current draw to ensure it operates within safe limits. When the relay circuit shorts to battery voltage, the ECU detects abnormally high voltage on the control line instead of the expected modulated signal. The fault triggers when voltage remains at or near battery potential when it should be switched or grounded.

Voltage & Parameter Thresholds