Testing Lambda Probe Heating - Audi A8 1994 Service Manual

Motronic injection and ignition system (6-cylinder) - Edition 02.1999
Reading Display Group 33
Display Group 33
Display zone 2 / 4
Approx. 0.450 V - Open circuit in wire 4 between lambda
probe and control unit
- Open circuit in wire 3 between lambda
probe and control unit
More than 1.100 V - Short to positive in wire 4 between lambda
Protected by copyright. Copying for private or commercial purposes, in part or in whole, is not
probe and control unit
permitted unless authorised by AUDI AG. AUDI AG does not guarantee or accept any liability
with respect to the correctness of information in this document. Copyright by AUDI AG.
Less than 0.150 V - Short to earth in wire 4 between lambda
probe and control unit

2.4 - Testing lambda probe heating

Note:
The lambda probe heating circuit is monitored by the self-diagnosis system.
Interrogate fault memory => Page
- Connect vehicle diagnostic, testing and information system VAS 5051 (or fault reader V.A.G 1551) and
select engine electronics control unit by entering address word "01" ( => Page
When doing this the engine must be idling.
-> Indicated on display:
Rapid data transfer
Select function XX
- Press keys 0 and 8 for the function "Read measured value block" and confirm entry with Q key.
-> Indicated on display:
Read measured value block
Enter display group number XXX
- Press keys 0, 4 and 1 for "Display Group 41" and confirm entry with Q key.
-> Indicated on display:
Read measured value block 41
1 2 3
- Check resistance of lambda probe heating.
Display Group 41: Lambda probe heating, Bank 1 (at idling speed)
Display
Indicates
Range
Specification
Possible cause of fault
4 .
HELP
4
1
x.xx Kω
Bank 1, Probe 1
min.: 0 Kω
max.: 100 Kω
less than2 Kω
Audi A8 1994 ➤
Fault remedy
- Test signal wire and activation => Page
60
- Test lambda probe wiring
for Bank 1, Probe 1 => Page
- Test lambda probe wiring
for Bank 2, Probe 1 => Page
2
Display zones
2
Htg.bC.ON
Status of heating
Htg.bC.ON
Htg.bC.OFF
Htg.bC.ON
2.3 - Testing lambda probe and lambda control
60
62
.)
3 4
57