The autolamp delay circuit has an open wire or connection, preventing the headlights from dimming gradually after the engine shuts off. Think of it like a light switch that's broken and won't let electricity flow to activate the delay timer.

The ECU monitors voltage and continuity in the autolamp delay circuit to ensure the relay can energize and de-energize the headlight dimming function. When resistance exceeds thresholds or the circuit becomes open, the ECU cannot control the delay timing and triggers a fault code.

Voltage & Parameter Thresholds