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 B1591 GMC 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 Left Mirror and the Right Mirror Vertical Position Sensors are Potentiometers. The Driver Door Module (DDM) and the Passenger Door Module (PFDM) determine the vertical position of the mirrors based on the signal voltage from these sensors. The code will be set when the signal voltage of the mirror vertical position sensor is above or below the range limits, within 10%, for 30 seconds in the requested position. The voltage range limits depend upon what the actual voltage of the 5 volt reference circuit is, and will vary from vehicle to vehicle and from module to module.
Need more information on how to fix the B1591 GMC code? Get Access to Factory Service Manuals
Get the B1591 GMC code diagnosed by a professional: Find a repair shop in your area