With Manufacturer's Scan Tool

Diagnostic Functions, Climate Control Module

General







The control module has a built-in diagnostic system, the Volvo on-board diagnostic (OBD) system. This system continuously monitors itself 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. The control module can store up to 42 diagnostic trouble codes (DTCs). If the number of diagnostic trouble codes (DTCs) exceeds ten, the five first diagnostic trouble code (DTC)s will always be saved, until erased in the workshop. The other five diagnostic trouble codes (DTCs) will be overwritten. If an eleventh diagnostic trouble code (DTC) is stored it overwrites the diagnostic trouble code (DTC) stored in the sixth position and so on.

Every diagnostic trouble code (DTC) has a counter which records the number of cycles which have been "fault-free" since the diagnostic trouble code (DTC) was stored (intermittent fault). A cycle is defined as the period from when the ignition was turned on, was then on for at least 10 seconds and then turned off. Every time the cycle runs without the control module registering the fault again, the counter increases by 1. Using the counter, it is possible to determine if the control module interprets the diagnostic trouble code (DTC) as permanent or intermittent. When the counter is at 0, the control module treats the malfunction as a permanent fault. If the counter value is greater than 0 the control module interprets this as meaning the fault is intermittent.

Reading off the Volvo on-board diagnostic (OBD) system
Fault and other information can be read using the VADIS PC connected to the data link connector (DLC) which is located on the left of the center console (for right-hand drive cars on the right of the center console).

Volvo On-board Diagnostic (OBD) System
With the VADIS PC it is possible to:
- read off and erase diagnostic trouble codes (DTCs), counters and frozen values
- continuously monitor the values and status of the input and output signals for the signals
- self-adjust the damper motors
- program the control module with certain information
- read off the control module identification.

The following conditions must be met before the Volvo on-board diagnostic (OBD) system is activated:
- the ignition must be on
- the battery voltage must be normal.

NOTE: For self-adjustment of the damper motors the engine must be running at idle (generator (GEN) charging).

Reading and erasing diagnostic trouble codes (DTCs)
Stored diagnostic trouble codes (DTCs) and counters can be read off and erased using this function. The on-board diagnostic (OBD) system can identify 42 different faults in the form of diagnostic trouble codes (DTCs).

Diagnostic trouble codes (DTCs) can only be erased when all diagnostic trouble codes (DTCs) have been read at least once.