P0894 GMC - Torque Converter Clutch Fluid Diagram
- Dirty or contaminated fluid
- Internal transmission failure
The Powertrain Control Module (PCM) monitors the difference between engine speed and transmission output speed. In D3 drive range with Torque Converter Clutch (TCC) engaged, the engine speed should closely match the transmission output speed. In D4 drive range, with the TCC engaged, the TCC slip speed should be -20 to +50 RPM.