Check the 'Possible Causes' listed above. Visually inspect the related wiring harness and connectors. Check for damaged components and look for broken, bent, pushed out, or corroded connector pins.
The cost to diagnose the B1578 code is 1.0 hour of labor. The diagnosis time and labor rates at auto repair shops vary depending on the location, make and model of the vehicle, and even the engine type. Most auto repair shops charge between $75 and $150 per hour.
The Smart Junction Box (SJB) monitors the parking lamp request input from the headlamp switch. The SJB provides a ground for the parking lamp relay coil (integrated into the SJB ) when a request for the parking lamps is received. When the parking lamp relay is energized, voltage is routed to the rear and front parking lamps. The Diagnostic Trouble Code (DTC) sets when the SJB detects a short to ground from the parking lamps on input circuit.
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