Control Module: Description and Operation

Transmission Control Module

Description
The TCM performs four self-test integrity diagnostics on its internal hardware and software to check for faults. A fault is detected if: -
1. The diagnostic drive cycle is active and an electrical fault of the ground return line has been detected.
2. The engine speed is greater than 420 RPM, the diagnostic drive cycle is active and the supply voltage is greater than 18 volts or less than 8 volts.
3. The calculated checksum does not match the stored checksum.
4. The diagnostic drive cycle is active and the incorrect calibration file has been selected.