Start by checking 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's pins.
The cost to diagnose the B12CA Mercury code is 1.0 hour of labor. The auto repair's diagnosis time and labor rates vary by location, vehicle's make and model, and even your engine type. Most auto repair shops charge between $75 and $150 per hour.
The stop-start disable button is a momentary contact switch. It is normally open, Controlled Area Network (CAN) signal low. Closed (button being pushed) is CAN signal high. The Front Controls Interface Module reads the switch status and sends it over CAN to the Powertrain Control Module (PCM). If the button is stuck open, there are no low to high transitions. Since the PCM does not recognize a button push, stop-start will not be disabled if requested by the customer. If the button is stuck closed, there are no low to high transitions. Since the PCM does not recognize a button push, stop-start will not be disabled if requested by the customer.
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