Description of On-Board Diagnostics
Digital Climate Control - Climatronic On Board Diagnostic (OBD)
NOTE: Some components and functions of the Climatronic system are not monitored by On Board Diagnostic (OBD) (e.g.:interior temperature sensor fan -V42-). If there is a specific complaint and no malfunctions are recognized after checking the Diagnostic Trouble Code (DTC) memory, refer to the information listed below.
Function
The Climatronic control module -J255- receives input information from various electrical and electronic components (sensors). This information is processed by the control module in accordance with specified values and then provides corresponding output signals that control electrical components (actuators).
The Climatronic control module -J255- is integrated into the A/C control head -E87- and cannot be serviced separately. To enable recognition of component malfunctions or if there is an open circuit, the control module is equipped with Diagnostic Trouble Code (DTC) memory which can be checked using the VAG 1551/1552 Scan Tool (ST) or VAS 5051 Vehicle Diagnostic Testing and Information System.
Should a malfunction be detected in a monitored sensor or component, it is stored in the Diagnostic Trouble Code (DTC) memory.
When malfunctions which have a permanent adverse effect on the operation of the Climatronic are stored in DTC memory, the A/C control head -E87- display flashes for approx. 15 seconds when the ignition is switched on. On malfunctions that do not cause the display to flash, the Climatronic control module allows Climatronic operating in emergency mode at the settings set on the display.
To determine malfunctions, initiate the On Board Diagnostic (OBD) program and retrieve stored information with the VAG 1551/1552 Scan Tool (ST) or VAS 5051.
Malfunction information displayed by the scan tool is listed on Diagnostic Trouble Code (DTC) tables containing notes on possible causes and repairs.
Technical data
Memory: Permanent
Data output: Rapid data transfer
Check Diagnostic Trouble Code yes
(DTC) memory:
Output Diagnostic Test Mode (DTM): yes
Basic setting: yes
Coding control module: yes
Read Measuring Value Block: yes
Test prerequisites
- All fuses OK according to wiring diagram.
- Battery (B+) voltage: minimum 11.5 V.
- Both battery terminals checked for tightness.
List of available functions
Function
01 - Check control module version
02 - Check Diagnostic Trouble Code (DTC) memory
03 - Output Diagnostic Test Mode (DTM)
04 - Basic setting
05 - Erase Diagnostic Trouble Code (DTC) memory
06 - End output
07 - Coding control module
08 - Read measuring value block
Only the functions listed can be used at present.
After pressing the -> button, the Scan Tool (ST) program returns to the initial position.