Circuit/System Testing
WARNING: This page does not describe the selected car, but rather 8 other vehicles, including the 2011 GMC Yukon XL, 2011 GMC Yukon, 2011 Chevrolet Tahoe, 2011 Chevrolet Suburban, and 2011 Chevrolet Avalanche. However, it is still accessible from the selected car via links, so may be relevant.
- Perform the Line Pressure Check . Verify the transmission line pressures are within the specified ranges.
- If not within the specified ranges, refer to Fluid Pressure High or Low .
- Ignition OFF, remove the Q8 control solenoid valve assembly. Refer to Control Solenoid Valve and Transmission Control Module Assembly Replacement .
- Perform the Control Solenoid Valve and Transmission Control Module Assembly Solenoid Performance Test . Test all solenoids on the Q8 control solenoid valve assembly. A pressure change should occur for each solenoid valve.
- If the Q8 control solenoid valve assembly does not pass the performance test, replace the Q8 control solenoid valve assembly.
- Listed in the chart below are conditions for each component that could set DTC P0756. Carefully inspect each component for that condition. Repair or replace as necessary.
| DTC | Component | Condition |
|---|---|---|
| P0756 | Lower Control Valve Body (351) | Clutch select valve 3 stuck off - debris, sediment, binding or scored bore |
| P0756 | Lower Control Valve Body (351) | Bore Plug - Clutch Select Valve 3 leaking, undersized bore plug, damaged |
| P0756 | Lower Control Valve Body (351) |
|
| P0756 | Q8 Control Solenoid Valve Assembly (314) | Shift Solenoid (SS) 2:
|
| P0756 | 1-2-3-4 and 3-5-R Clutch Housing Assembly (51) | 1-2-3-4 clutch backing plate retaining ring not seated, causing the piston to over travel and cut the 1-2-3-4 clutch piston seal |
| P0756 | Fluid Pump Cover Assembly | Fluid pump cover vanes and fluid pump rotor broken |
| P0756 | Low Clutch Sprag Assembly | Broken or incapable of holding torque |
| P0756 | Pump Seal | Seal is cut, torn causing a leak due to pump speed and capacity |