VCC Transmission Retard Position Set Up Tools A special tool (see Service Procedures Workshop Manual for correct tool number) is used to rotate the transmission to the full retard position when checking the piston position with an ohmmeter. This tool engages the inner hub of the transmission to provide an easy method of twisting it to the left for the ohmmeter test. Diagnostics The VCC is fully compatible with the diagnostic software providing specific fault codes and test modules. Additionally, diagnostic requests section provides status of the PWM of the VCC solenoids and camshaft position feedback via the camshaft position sensors. The Service Functions section of the TestBook/T4 also provides a VCC system test.