Diagnostic Functions

Diagnostic functions

General
The control module has a built-in diagnostic system, Volvo Diagnostic, which continuously monitors internal functions as well as input and output signals.

Diagnostic trouble codes (DTCs)
If the control module detects a fault then it stores a diagnostic trouble code. If a fault disappears for any reason after a diagnostic trouble code has been permanently stored in the control module then the information on the fault remains in the control module.
In some instances, the incorrect signal is replaced with a substitute value or restricts certain functions. Any DTCs are stored in the memory on the control module and the information can be read out using VIDA.

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 once all the diagnostic trouble codes (DTCs) have been read off at least once.

Note! Certain functions are unavailable until the diagnostic trouble codes (DTCs) have been erased.

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

Reading off extended fault-tracing information
This function can be used to read parameters, status identifiers and counters stored at the same time as a diagnostic trouble code (DTC). These are called frozen values.