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)
A diagnostic trouble code (DTC) is stored if the control module detects a fault. A fault which is detected in the most recent operating cycle is defined as permanent. Other faults which are detected are defined as intermittent.
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 in the control module.
If a fault is no longer permanent, the diagnostic trouble code (DTC) remains as intermittent.

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.