Checking and Erasing DTC Memory
Test conditions- All fuses OK as per wiring diagram
NOTE: DTC memory must be checked before it can be erased.
Main control program of A/C control head -E87- is switched OFF during On Board Diagnostic (OBD). Climate control regulation does not take place during OBD (compressor, radiator fan, etc. are not controlled).
Check DTC Memory - function 02
- Start engine.
- Press "Auto" button on A/C control head.
- Drive vehicle a few yards at walking speed.
- Connect VAG 1551 scan tool to Data Link Connectors (DLC) in auxiliary relay panel I (left side of water plenum) using diagnostic cable VAG 1551/1 as follows:
- Remove cover from auxiliary relay panel I in plenum.
- Connect black connector to black DLC (battery positive voltage (B+) supply to DLC).
- Connect white connector to white DLC.
Blue connector is not used.
NOTE If there is no display on VAG 1551, check B+ supply to black DLC.
Operating modes -1- and -2- appear alternately
V.A.G - On Board Diagnostic HELP
1 - Rapid data transfer
2 - Blink code output
NOTE:
- Press the HELP button to obtain additional operating information.
- Press the -> button to step through program sequence.
- Switch printer ON with print button (button lights up).
- Press -1- button to select "Rapid data transfer" operating mode 1.
Indicated on display
Rapid data transfer HELP
Insert address word XX
- Press buttons -0- and -8- to select "AC/Heating Electronics" address word 08.
Indicated on display
Rapid data transfer Q
08 - AC/Heating Electronics
- Press -Q- button to confirm input.
Indicated on display
4A0820043A Klima-Vollautomat DXX ->
Coding 052 WSC 23890
Control module identification and coding are displayed.
NOTE: For proper part number and application of A/C control head -E87- See current parts catalog.
Code description
The three-digit control module code is broken down as follows:
1st Digit
Code Application
0 not used
2nd Digit
Code Application
6 6-cylinder engine
5 5-cylinder engine
3rd Digit
Code Country Application
2 USA/Canada Gasoline
NOTE: For A/C control head coding procedure. Coding A/C Control Head (Function 07) Display "DXX" indicates software version of A/C control head -E87- and has no applications with OBD.
If either display appears as shown:
Rapid data transfer HELP
Control module does not answer
Rapid data transfer HELP
K wire not switching to Ground
Rapid data transfer HELP
K wire not switching to B+
- Press HELP button to print out list of possible causes.
Rapid data transfer HELP
Error in communications link
- Check wire connections of DLC.
After repairing possible malfunctions:
- Press -0- and -8- buttons to select "AC/Heating Electronics" address word 08.
- Press -Q- button to confirm input.
- Press -> button.
Indicated on display
Rapid data transfer HELP
Select function XX
- Press buttons -0-and -2- to select "Check DTC Memory" function 02.
Indicated on display
Rapid data transfer Q
02 - Check DTC Memory
- Press -Q- button to confirm input.
Number of stored malfunctions or "No DTC recognized" will be displayed and printed out one after another
X DTC recognized ->
- Repair any malfunctions as necessary.
If display appears as shown
No DTC recognized ->
- Press -> button (after last malfunction has been displayed/printed).
Indicated on display
Rapid data transfer HELP
Select function XX
If A/C compressor clutch does not engage, or if fresh air blower speed cannot be regulated, even though no malfunction was recognized:
- Read measuring value block.
- Perform output DTM.
Erase DTC Memory - function 05
- Check DTC memory.
Indicated on display
Rapid data transfer HELP
Select function XX
- Press buttons -0- and -5- to select "Erase DTC Memory" function 05.
Indicated on display
Rapid data transfer Q
05 - Erase DTC Memory
- Press -Q- button to confirm input.
If display appears as shown
Attention! ->
DTC memory is not interrogated
- Check DTC memory following the procedure sequence in exact order.
NOTE: If ignition was switched OFF or if engine speed (RPM) exceeded 4000 between checking DTC memory and erasing, DTC memory will NOT be erased.
Indicated on display, if DTC memory is successfully erased
Rapid data transfer ->
DTC Memory is erased
- Press -> button.
Indicated on display
Rapid data transfer HELP
Select function XX
- Perform basic setting.