A/C System On Board Diagnostic
A/C System On Board Diagnostic
Pay attention to the following if testers and measuring instruments have to be used in the course of a test drive:
CAUTION!
• Always attach testers and measuring instruments to back seat and have them operated from there by a second person.
• If testers and measuring instruments were to be operated from front passenger's seat, person sitting there could suffer injury in the event of an accident due to triggering of front passenger's airbag.
• There are different versions of the climatronic control module (J255) control head. Therefore follow coding exactly when replacing an A/C control head.
• Depending on the date of manufacture, the A/C control head Climatronic Control Module (J255) has also been designated as A/C Control Head (E87) in various sources of repair information (e.g. in wiring diagrams for vehicles up to model year 2004).
• For this vehicle the diagnostic connections of various control modules (e.g. Radio) have been routed to a different pin on the Data Link Connector (DLC). In order to be able to exchange data with these control modules, K-wire adapter (VAS 6017B) (or K-wire adapter (VAS 6017A)) must be inserted in the diagnostic cable between vehicle and vehicle diagnostic tester (e.g. Vehicle Diagnosis, Testing and Information System (VAS 5051A) or Vehicle Diagnosis, Testing and Information System (VAS 5052)).
• As of vehicle identification number (VIN) "400000" of model year 2005 (Sedan and Avant) and "012913" of model year 2005 (Cabrio), certain control modules are no longer connected to the K/L wire of the 16-pin DLC of the vehicle (e.g. Engine Control Module (ECM) (J623), Transmission Control Module (TCM) (J217), airbag control module (J234), etc.), depending on vehicle equipment, These control modules exchange information via "CAN-data wires" e.g. using Vehicle Diagnosis, Testing and Information System ( VAS 5051A). Since these connections are not present in the K-wire adapter (VAS 6017A), the K-wire adapter (VAS 6017B) is required for On Board Diagnostics (OBD) of these control modules.
• For OBD using Fault Read Out Device (V.A.G 1551) or Mobile Scan Tool (V.A.G 1552), it is required that the program card in Fault Read Out Device ( V.A.G 1551) matches at least data version "No. 9" and in Mobile Scan Tool (V.A.G 1552) at least data version "No. 6" for this vehicle. For vehicles as of Vehicle Identification Number (VIN) "400000" of model year 2005 (Sedan and Avant) and "012913" of model year 2005 (Cabrio), it is no longer possible to perform OBD for all vehicle systems using Fault Read Out Device (V.A.G 1551) or Mobile Scan Tool (V.A.G 1552).
On Board Diagnostic Technical Data
• The fault memory is designed as a non-volatile memory and is thus independent of the power supply.
• Data transfer between Climatronic Control Module ( J255) and Vehicle Diagnosis, Testing and Information System (VAS 5051A), Vehicle Diagnosis, Testing and Information System (VAS 5052), Fault Read Out Device (V.A.G 1551) or Mobile Scan Tool (V.A.G 1552 ) is performed in the operating mode "Rapid Data Transfer ".
Function
The A/C control head, Climatronic Control Module ( J255), is equipped with DTC memory.
After evaluation, the A/C control head, Climatronic Control Module (J255) differentiates between different malfunctions, refer to => [ DTC Table ] DTC Memory, Interrogating and saves those malfunctions until DTC memory is erased after DTC memory is checked.
Fault Finding
Faults occurring in monitored sensors or components are stored in fault memory together with an indication of the type of fault.
The first step in the fault-finding process is always to start self-diagnosis and interrogate the faults stored. This can be implemented by way of the following:
• Diagnostic Operating System (VAS 5051A)
• Vehicle Diagnosis, Testing and Information System ( VAS 5052)
• Fault Read-Out Device (V.A.G 1551)
• Mobile Scan Tool (V.A.G 1552)
The fault information displayed is used in conjunction with a fault table (containing information on possible causes of trouble) to perform pin-pointed repair measures.
• If a fault condition exists for longer than a pre-determined period, the fault is stored as being static. If the fault condition is then no longer detected for a pre-determined period, the fault is re-classified as being a sporadic fault. This process is constantly repeated. Sporadic faults are additionally identified as such by /SP on the display.
• A sporadic fault is erased automatically if it no longer occurs for a pre-determined period.
The On Board Diagnostic (OBD) options can only be performed using Vehicle Diagnosis, Testing and Information System (VAS 5051A ), Vehicle Diagnosis, Testing and Information System (VAS 5052), Fault Read Out Device (V.A.G 1551 ) or Mobile Scan Tool (V.A.G 1552), in mode "1" (Rapid Data Transfer).
The on board diagnostic (OBD) is not just limited to saving, checking, deleting, and the output diagnostic test mode, but also offers additional options with the basic setting, control module identification, adaptation, and coding.
Operating mode "2" (blink code output) is not provided for the air conditioner/heater electronics. Operating modes "3" (self-test) and "4" (operation identification) only affect the Fault Read-Out Device (V.A.G 1551) and the Mobile Scan Tool (V.A.G 1552) and are described in the corresponding operating instructions.
Available Functions
* 1- Version of control modules is always displayed on Vehicle Diagnosis, Testing and Information System (VAS 5051A) during On Board Diagnostic (OBD).
* 2- Output diagnostic test mode is possible only up to 3000 RPM and a vehicle speed of less than 3 mph (5 km/h). The A/C compressor regulator valve (N280) is activated by the Climatronic control module (J255) A/C control head only when the engine is not running. The request to activate the coolant fans (1 to 100%) is transmitted by the Climatronic control module (J255) A/C control head via the comfort and powertrain data bus system to the respective engine control module. The coolant fans (V7) are switched on by the engine control module only when the engine is running. Refer to => Vehicle Diagnosis, Testing and Information System VAS 5051 in the "guided fault finding" function.
* 3- The basic settings (e.g. country version, left or right steering, etc.) of the Climatronic control module (J255) A/C control head are coded in this vehicle by the instrument cluster control module (J285). The data is transmitted via the comfort data bus system to the Climatronic control module (J255) A/C control head, and the currently valid coding is displayed in the measured value block. Direct input of coding into the Climatronic control module (J255) A/C control head is only provided for certain equipment (e.g. heated windshield (Z2) or sunroof with solar cells, etc.)
* 4- As of hardware/software version " 0711" of the Climatronic control module (J255) A/C control head, the VIN transmitted by the comfort data bus system is stored during the first operation of the Climatronic control module (J255) A/C control head. If this Climatronic control module (J255) A/C control head is installed in another vehicle, this VIN must be deleted via the "adaptation" function.
• The on board diagnostic with the Vehicle Diagnosis, Testing and Information System (VAS 5051A) is described in this repair information.
• The on board diagnostic can be performed with the Vehicle Diagnosis, Testing and Information System (VAS 5052), the fault read-out device (V.A.G 1551) or the mobile scan tool (V.A.G 1552) in the same manner. To be able to document any faults during subsequent queries, it is beneficial to connect the Vehicle Diagnosis, Testing and Information System (VAS 5051A) or the fault read-out device ( V.A.G 1551) and to print out any faults (the mobile scan tool (V.A.G 1552) is not equipped with a printer) prior to deleting the DTC memory.
• If a new Climatronic control module (J255) A/C control head was installed, and if no basic setting was performed after installation, the A/C compressor regulator valve (N280) is not activated, and compressor shutoff condition "6" is displayed in measured value block display group "002".
• When starting on board diagnostic, A/C system regulation is not interrupted. However, it is switched off when selecting the following functions: " output diagnostic test mode", "perform basic setting".
• When selecting other functions, regulation remains completely functional.
• Installation locations of A/C system components, refer to => [ A/C System Control and Regulation Components ] A/C System Control and Regulation Components.