Circuit Operation

CIRCUIT OPERATION
The transmission control system is used on all automatic transmission applications. It provides smooth and accurate shift points and can adjust as the transmission wears.

Power for the Transmission Control Module (TCM) is supplied from three sources. One is a direct battery feed on circuit A14. This circuit is protected by a 20 Amp fuse located in the Power Distribution Center (PDC) cavity B. This circuit is spliced and supplies power for the transmission control relay.

A switched power input is also supplied, to the TCM, on circuit A41. This is the power supply is for the engine starter relay, coil side, and is HOT in the START position only. Circuit A1, which connects to the ignition switch, supplies power to circuit A41 in the START position and is protected by a 20 Amp fuse located in cavity A of the PDC.

Circuit F11 also supplies a switched power input to the TCM and is HOT when the ignition switch is in the OFF/RUN/START position. This circuit is protected by a 5 Amp fuse located in the cavity 17 of the junction block. Power for the fuse is supplied on circuit A81. This circuit, A81, is powered by circuit A1 from the PDC. Circuit A1 is protected by a 20 Amp fuse located in cavity A of the PDC.

Ground for the TCM is supplied on the Z13 circuit, which is a power ground, and circuit Z14, which is a signal ground. Both grounds terminate at the left front frame rail.

The CCD Data Bus is used to allow the controller to communicate with other controllers and the universal data link connector. The circuits involved are, D1 for CCD (+), and D2 for CCD (-).

Circuits D6 and D21 are used to allow the TCM to communiate with the universal data link connector. The D6 circuit is used as the SCI receive line, and the D21 circuit is used for the SCI transmit line.