Code : P1839
Make : BUICK
Description : P1839 BUICK Internal Mode Switch ‘C’ Circuit Low Voltage
Possible causes :
– Faulty Manual Shift Shaft Position Switch Assembly
– Manual Shift Shaft Position Switch Assembly harness is open or shorted
– Manual Shift Shaft Position Switch Assembly circuit poor electrical connection
Solutions :
– Carry out a Reset via CarDiag
– Choose a better quality fuel
– Check that the tank cap is securely closed
– Check the oil level and add more if it is lower than MAX
– Restart an Automatic diagnostic via CarDiag
– If the fault persists, you can check the “Possible causes” listed above : visually inspect (by yourself (tutorials to come) or by a professional) the wiring harness and the associated connectors, check for damaged components, and look for broken, bent, pushed, or corroded connector pins.