Transmission Control Systems: Description and Operation

Transmission control module (TCM) diagnostic functions

General




The control module has a built-in diagnostic system, the Volvo on-board diagnostic (OBD) system. This system continuously monitors its own system and the input and output signals.

Diagnostic trouble codes (DTCs)
The control module will store a diagnostic trouble code (DTC) if it detects a fault. If a fault disappears for any reason after the diagnostic trouble code (DTC) has been permanently stored in the control module, information about the fault remains stored in the control module.

Reading and erasing diagnostic trouble codes (DTCs)
Stored diagnostic trouble codes (DTCs) can be read off and erased using this function.
Diagnostic trouble codes (DTCs) can only be erased when all diagnostic trouble codes (DTCs) have been read at least once.

Reading off input and output signals
Using this function, the status of the control module input and output signals can be continuously read off.
For further information about parameters, see Description of parameters Description of Parameters.

Activating components
This function allows components to be activated so that their functions can be checked.
For further information about activations, see Description of activations Description Of Activations.

Reading off the control module identification
VIDA identifies the control modules by reading off a number of codes from the control module memory.
The codes contain the following information about the control module:
- hardware P/N (control modules without software)
- hardware serial number (control modules without software)
- software P/N
- diagnostic software P/N