Circuit/System Testing

WARNING: This page is about a different car, the 2010 GMC Sierra, 2010 GMC Cab & Chassis Sierra, 2010 Chevrolet Silverado, and 2010 Chevrolet Cab & Chassis Silverado. 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.
- 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 P0741 or P0742. Carefully inspect each component for that condition. Repair or replace as necessary.

DTC	Component	Condition
P0741 P0742	A/Trans Fluid Pump Cover Assembly (219)	TCC Control Valve (227) stuck / sticking - debris, binding, damaged valve, or scored bore Converter Feed Limit Valve (220) stuck / sticking - debris, binding, damaged valve, or scored bore Pressure Regulator Valve (233) stuck / sticking - debris, binding, damaged valve, or scored bore Turbine Shaft Bushings (218), (228) damaged or loose Leak between stator / tower assembly and cover
P0741	4-5-6 (w/Turbine Shaft) Housing Assembly (441)	TCC Turbine Shaft O-Ring Seal (443) damaged or leaking
P0741	Torque Converter Assembly (1)	TCC friction material debonded or excessively worn One way stator clutch distressed Internal leak - missing or damaged seal Overheated due to lack of lubrication / cooler flow
P0741 P0742	Lower Control Valve Body Assembly (351)	TCC Regulator Apply Valve (355) stuck / sticking - debris, binding, damaged valve, or scored bore. Bore plug (328) undersized or leaking Clutch Select Valve 2 (352) stuck / sticking - debris, binding, damaged valve, or scored bore
P0741 P0742	Q8 Control Solenoid Valve Assembly (314)	TCM incorrectly reporting high OSS, causing early TCC apply or late TCC release
P0742	B14A/b14C A/Trans Input and Output Speed Sensor Assembly (303)	Incorrect (high) OSS signal, causing early TCC apply or late TCC release
P0741	Control Solenoid Valve Assembly (21)	A/Trans Fluid Pump Seal Assembly (18) damaged or leaking
P0741	Torque Converter (w/Fluid Pump) Housing Assembly (203)	Torque Converter Bushing (206) damaged or loose
P0741	Torque Converter Diagnosis	Refer to No Torque Converter Clutch Apply .
P0742	Torque Converter Diagnosis	Refer to No Torque Converter Clutch Release .