If you have had continuing sluggish starts and other electrical problems and you are certain that you have a strong alternator, generating an output of 14V, you may want to look closely at your positive battery cable. This is often a common area of electrical trouble, especially for internal corrosion.
Sprinter II 2014-2016 4 CYLINDER 2.1 LITER ONLY.
Fault codes often associated with a faulty cable....
P2526 -002 Boost Pressure Reg short to ground
P2526-001 Signal line shorted to voltage
P2530-002 Intake port EKAS shorted
P2527-002 EGR shorted
P2514-002 Vent heater valve shorted
P2978-002 EGR short to ground
P2376-001 Throttle valve under voltage