Connecting fault reader V.A.G 1551 and selecting functions — AUDI

Notes:

Vehicle systems tester V.A.G 1552 can also be used instead of fault reader V.A.G 1551.
The main programme of operating and display unit is switched off during self-diagnosis. No control cycle is carried out =>Page
01-6
.
On vehicles with stationary heater, it is also possible to interrogate the fault memory with stationary heater operating.
From software status D04 it is possible to alter the air flow in stationary heater mode (start always in position "Def" and "22 oC").
Vehicles with 6- and 8-cylinder engine 07.95 ▸ are equipped with a Nippondenso compressor (phased introduction). This compressor does not have a compressor speed sender -G111. In the event of a stiff compressor, the magnetic clutch is disengaged by an overheating cut-out in the magnetic clutch's solenoid.

Requirements:

Supply voltage of electrical system OK
All fuses OK:

=> "Current flow diagrams, Electrical fault finding and fitting locations" binder

Start the engine.
Press the "AUTO" button of operating and display unit -E87.

Drive the vehicle a few metres at walking speed.
Connect fault reader V.A.G 1551 with diagnostic cable V.A.G 1551/1 to diagnostic sockets as follows:
Remove cover of auxiliary relay carrier l in left of plenum chamber.
Plug in black connector to black diagnostic socket.

V.A.G - SELF DIAGNOSIS
HELP
1 - Rapid data transfer 1)
2 -Flash code output 1)
Indicated on display:

1)
appears alternately

Note:

If no display appears, do not plug in white connector. In this case, test power supply for black diagnostic socket => Page
01-144
.

Plug in white connector to white diagnostic socket (blue connector is not required).
Press PRINT key to switch on printer - (indicator lamp in key lights up).
Press key 1 for mode 1, "Rapid data transfer".

Rapid data transfer
HELP
Enter address word XX
When indicated on display:

Press keys 0 and 8 for address word "AC/heating electronics".

Rapid data transfer
Q
08 -AC/heating electronics
When indicated on display:

Confirm input with Q key.

Rapid data transfer
Tester transmits address word 08
When indicated on display:

Wait until the next display appears.

Control unit identification (examples)

4A0820043X Air conditioner-fully automatic DXX
⇒
Coding 00040
WSC XXXXX
When indicated on display (example):

Example for vehicles with Zexel compressor up to index H and 4-cylinder engine
- 4A0820043X: · Part no.
- Air conditioner-Vollautomat: · Control unit for fully automatic air conditioner
- DXX: · EPROM (Data)
- Coding 00040: · Different codes => Page 01-95
- WSC XXXXX: · Workshop Code for the V.A.G 1551 which was used to perform the last encoding

4A0820043K Air conditioner-fully automatic D05
⇒
Coding 00160
WSC XXXXX
When indicated on display (example):

Example for vehicles with Nippondenso compressor and 6-cylinder engine
- 4A0820043K: · Part no.; assignment / => Parts Catalogue
- Air conditioner-fully automatic: · Control unit for fully automatic air conditioner
- D04: · EPROM (Data)
- Coding 00160: · Different codes => Page 01-95
- WSC XXXXX: · Workshop Code for the V.A.G 1551 which was used to perform the last encoding

Note:

Depending on programme card version of V.A.G 1551, the first two digits do not appear in display (e.g. 140 instead of 00140).

Press ⇒key.

Rapid data transfer
HELP
Select function XX
When indicated on display:

Select a function => Page
01-42
.
A list of the possible functions is printed out after pressing the HELP key:

Notes on fault messages:

Control unit does not answer!
HELP
When indicated on display:

or

Rapid data transfer
HELP
K-line not switching to earth

or

Rapid data transfer
HELP
K-line not switching to positive

Print a list of possible fault causes by pressing the HELP key.
Check wiring of diagnostic socket => Page
01-144
.
After rectifying possible causes of fault, re-enter 0 and 8 for "AC/heating electronics" and confirm entry with Q key.

Rapid data transfer
HELP
Communication fault
When indicated on display:

Separate wiring between individual systems =>Page
01-149
and check wiring.