Possible causes
– Low transmission fluid level
– Dirty transmission fluid
– Faulty 2-3 Shift Solenoid Valve
– 2-3 Shift Solenoid Valve harness or connectors
– 2-3 Shift Solenoid Valve circuit is open or shorted
– Dirty transmission fluid
– Faulty 2-3 Shift Solenoid Valve
– 2-3 Shift Solenoid Valve harness or connectors
– 2-3 Shift Solenoid Valve circuit is open or shorted
When is the code detected?
When the Powertrain Control Module (PCM) detects a 4-3-3-4 shift pattern, then DTC P0756 sets.
Symptoms
– Engine Light ON (or Service Engine Soon Warning Light)
– Transmission will not shift gears.
– Transmission will not shift gears.
P0756 GMC Description
The 2-3 Shift Solenoid (SS) valve controls the fluid flow acting on the 2-3 shift valves. The 2-3 SS valve is a normally-open exhaust valve that is used with the 1-2 SS valve in order to allow four different shifting combinations.
GMC Technical Service Bulletins for P0756 code
2011 GMC SIERRA 061000 ENGINE AND ENGINE COOLING:ENGINE
2012 GMC SIERRA 061000 ENGINE AND ENGINE COOLING:ENGINE
2013 GMC SIERRA 061000 ENGINE AND ENGINE COOLING:ENGINE
2001 GMC SIERRA 2500 HD POWER TRAIN:AUTOMATIC TRANSMISSION
2001 GMC SIERRA 3500 POWER TRAIN:AUTOMATIC TRANSMISSION
2002 GMC SIERRA 2500 HD POWER TRAIN:AUTOMATIC TRANSMISSION
2002 GMC SIERRA 3500 POWER TRAIN:AUTOMATIC TRANSMISSION
2003 GMC SIERRA 2500 HD POWER TRAIN:AUTOMATIC TRANSMISSION
2003 GMC SIERRA 3500 POWER TRAIN:AUTOMATIC TRANSMISSION
2004 GMC SIERRA 2500 HD POWER TRAIN:AUTOMATIC TRANSMISSION