AUDI A4 1998 B5 / 1.G AC System On Board Diagnostic User Guide
Page 11 of 91
01-8
      
VAG1551 Scan Tool (ST), connecting; 
A/C control head -E87-, checking 
version
 
     
Battery Voltage OK
     Fuse 22 (S22) OK
     Ground (GND) connection on engine and 
transmission OK 
     
1996 vehicles  
    
-  Open rear passenger ashtray in center console and remove cover for 
Data Link Connector (DLC). 
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Page 12 of 91
01-9
 
    
-  With ignition switched off, connect VAG1551 Scan Tool (ST) to Data 
Link Connector (DLC) with cable VAG1551/3. 
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Page 13 of 91
01-10
      
1997  vehicles  
    
All vehicles   -  With ignition switched off, connect VAG1551 (VAG1552) scan tool to 
16-pin Data Link Connector (DLC) under dash to left of steering 
column, using adapter cable VAG1551/3. 
V.A.G - ON BOARD DIAGNOSTIC HELP1 - Rapid data transfer2 - Blink code output
    
Indicated on display 1)  1) Operating modes 1 and 2 are displayed alternately  
-  Switch on printer with -PRINT- button (indicator lamp in switch will light 
up). 
-  Switch on ignition or start engine.
-  Switch A/C compressor on (press "AUTO" button).
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Page 14 of 91
01-11
      
-  Press button -1- for operating mode "Rapid data 
transfer." Rapid data transfer 
HELP
Enter address word XX
    
Indicated on display  
Notes:  
If display is blank, check wiring to VAG1551/power supply using 
Troubleshooting Procedure No. 1 in "Electrical Wiring Diagrams, 
Troubleshooting and Component Locations" Manual. 
Address word for A/C Heating Electronics: 08 
Additional operating instructions can be obtained by pressing the 
HELP button on VAG1551 Scan Tool (ST) During testing procedures, the  button advances the program to the 
next step An incorrect entry can be cancelled with the -C- button
-  Press buttons -0- and -8-. 
Rapid data transfer  
Q
08 - A/C Heating Electronics
    
Indicated on display  
-  Press -Q- button to confirm input.
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Page 15 of 91
01-12
       If one of the following messages is displayed:  Rapid data transfer 
HELP
Control module does not answer
    
Indicated on display  
or  
Rapid data transfer 
HELP
K wire not switchin
g to B+
    
Indicated on display  
-  Press HELP button to print out list of possible causes.
Rapid data transfer No si
gnal from control module
    
-  Check wiring to Data Link Connector (DLC) according to wiring 
diagram   Electrical Wiring Diagrams, Troubleshooting & Component 
Locations binder. 
Rapid data transfer Error in communication link
    
If this display appears at the beginning of or during the OBD program, 
malfunctions have occurred and data transfer is no longer possible 
between the VAG1551 Scan Tool (ST) and the A/C control head -E87-.  
 Electrical Wiring Diagrams, Troubleshooting & Component Locations 
binder    -  Check wiring to DLC. 
Rapid data transfer  
Q
08 - A/C Heatin
g Electronics
    
-  After repairing possible causes of the malfunction, press buttons -0- 
and -8- to insert "AC/Heating Electronics" address word 08. 
-  Press -Q- button to confirm input.
Rapid data transfer Scan Tool sends address word 08
    
Indicated on display  
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Page 16 of 91
01-13
 
8D0820043D A4-Klimavollautomat DXX
 Coding 00062 WSC ZZZZZ
    
Indicated on display after approx. 5 seconds  
Readout example shows US/CDN version, Zexel A/C compressor, 6 
cylinder gasoline engine  
Coding -E87- and code tables   page 01
-57
 . 
8D0 820 043 D: Part Number of A/C control head -E87-A4: A/C Heating Electronics component designationDXX: Software version of A/C control head -E87-Coding: 00062WSC 06812: Dealership code
8L0 820 043B A4-
A/C full
y automatic DXX
Codin
g XXXXX 
WSC ZZZZZ
    
For m.y. 1997 vehicles install only A/C control head -E87- with Part No. 
8L0 820 043 up to and including Part No. index letter "C."  
8L0 820 043D A4-
A/C full
y automatic DXX
Coding XXXXX 
WSC ZZZZZ
    
For vehicles beginning m.y. 1998 install only A/C control head -E87- with 
Part No. 8L0 820 043 from Part No. index letter "D."  
CAUTION! 
Part numbers are listed here for reference only. Always check with 
your Parts department for the latest information. 
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Page 17 of 91
01-14
      
Part 
number  Comments  
8D0 820 
043 D - G   
Regulation is only switched off in 
On Board Diagnostic (OBD) 
during output diagnostic test 
mode and basic setting. 
 For vehicles with 6 cylinder 
engines, must only be combined 
with Zexel compressor. 
8D0 820 
043 after 
H  For all vehicles up to m.y. 96.  
8L0 820 
043 A - C  For all vehicles up to m.y. 97 (lighting 
via terminal 58 and 58d)  
8L0 820 
043 after 
D  For all vehicles up to m.y. 98 without 
radio navigation system up to VIN 
199999 of m.y. 1999 (lighting 
indirectly activated via terminal 58s).  
8D0 820 
043 K or L  Version with only one display (for 
vehicles with radio navigation system 
up to VIN 199999 of m.y. 1999)  
8D0 820 
043 after 
M  Version with only one display (for 
vehicles as of VIN 200000 of m.y. 
1999)  
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Page 18 of 91
01-15
      
Notes:  
     
Zexel A/C compressors were installed from 
start of production. During m.y. 1996, 
Nippondenso type compressors are installed as 
a running change. These compressors are not 
equipped with A/C speed sensor G111. 
     The A/C control head is coded to reflect the 
compressor type installed (Zexel or 
Nippondenso). 
     Vehicles equipped with Nippondenso (Denso) 
compressors must have A/C control head with 
Part No. index "H" or higher installed to allow 
for correct coding. 
     Follow coding exactly when replacing an A/C 
control head -E87-. 
     
       Parts catalog microfiche   
     
A/C control head varies after VIN 200000 of 
m.y. 1999 for vehicles with and without radio 
navigation system (or a radio with a large 
control panel), with and without switch for 
heated seats (e.g. index "M", "N", "P" or "Q"). 
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Page 19 of 91
     
       Parts catalog microfiche        
Depending on VAG1551 Scan Tool (ST) program card version, 1st and 2nd digit may not 
be displayed (readout: e.g. 040 instead of 
00040). 
     Software version of control head is of no 
significance for service department. 
     If a replacement control head is not coded after 
installation or if an unrecognized code was 
entered, code "00042" (4-cyl. gasoline engine 
USA) is stored. 
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Page 20 of 91
01-16
      
Safety precautions
 
      If special testing equipment is required during 
road test, note the following:  
     
WARNING! 
     
Special testing equipment must always be 
secured on the back seat and must be 
operated from there by a 2nd person. 
     If special testing equipment were to be 
operated from the passenger seat, there 
could be injuries to the person seated there 
in the event of an accident and air bag 
deployment. 
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