Circuit/System Testing

WARNING: This page is about a different car, the 2009 GMC Sierra, 2009 GMC Cab & Chassis Sierra, 2009 Chevrolet Silverado, and 2009 Chevrolet Cab & Chassis Silverado. However, it is still accessible from the selected car via links, so may be relevant.

NOTE: You must perform the Circuit/System Verification first.

WARNING: Chock the wheels to prevent the vehicle from moving. Failure to chock the wheels can cause personal injury when the electrical system is repaired.

Perform a line pressure test. Refer to Line Pressure Check .
- If line pressure is low in all ranges, refer to Low Main Line Pressure in All Ranges .
- If line pressure is low in a specific range or ranges, refer to Low Main Line Pressure in Specific Ranges, Normal Pressure in Other Ranges .
Engine idling, shift selector in park, record line pressure. Use the scan tool to command the TCC Control Solenoid ON and verify the TCC PC Sol. Pressure Command parameter changed from 0 kPa (0 psi) to 1,600 kPa (232 psi). Record the line pressure after the pressure stabilizes. Line pressure should drop when the TCC Control Solenoid is commanded ON.
- If the pressure did not drop, refer to Control Valve Body Assembly Disassemble and Control Valve Body Cleaning and Inspection . If valve body inspection is normal, replace the TCC Solenoid. Refer to Control Valve Solenoid Replacement (SS1, SS2, SS3, TCC, and MAIN MOD) or Control Valve Solenoid Replacement (PCS1 and PCS2) . If line pressure still does not drop, refer to Transmission Fluid Pump Cover Disassemble .
If the above tested normal, replace the torque converter. Refer to Torque Converter Replacement .