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. The diagnostic trouble codes (DTCs) are stored in the RAM (random access memory) until the ignition is switched off. This means that if the steering wheel module (SWM) is removed before the key is removed from the ignition or turned to the 0 position, the non-programmed EEPROM diagnostic trouble codes (DTCs) disappear.
A fault which is detected in the most recent operating cycle is defined as permanent. Other faults which are detected are defined 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.

Reading off input and output signals
This function can be used to continuously read off the status of the control module's input and output signals.
For further information about parameters, see: Description of parameters, B5254T7 Scan Tool Testing and Procedures

Reading off extended diagnostic trouble code (DTC) 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.

Reading 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.