LEMON Manuals: Even more car manuals for everyone: 1960-2025
Home >> Volvo >> 2014 >> XC70 T6 >> Repair and Diagnosis >> Accessories & Equipment >> Headlights >> Lighting - Design And Function >> Headlamp Control Module (HCM) >> Headlamp Control Module (HCM) [2010-2011] >> Diagnostic Functions
April 5, 2026: LEMON Manuals is launched! Read the announcement.

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 are defined as intermittent. An operating cycle involves ignition on, the vehicle speed exceeding 20 km/h and the ignition being switched off.

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 more information about parameters, see the appropriate Vehicle communication information in Specifications, other.

ACTIVATING COMPONENTS 

This function can be used to activate components to check that they are working.

For more information on activations, see the appropriate Vehicle communication information under Specifications, other.

READING OFF THE CONTROL MODULE IDENTIFICATION 

The diagnostic tool identifies control modules by reading off a number of codes from the control module memory.

The codes contain the following information about the control module: