Audi Workshop Service and Repair Manuals

Special tools, testers and workshop equipment required

• ◆ V.A.G 1526 A
• ◆ V.A.G 1594 A
• ◆ V.A.G 1598/31
• ◆ VAS 5051 with VAS 5051/1

• or

• ◆ V.A.G 1551 with V.A.G 1551/3 A

Installation position => Overview installation positions - Page 24-5

Notes:

• ◆ For specific fault search, it is possible to switch off the Lambda control by selecting display group 99 "Basic setting" mode and to switch it on again by selecting display group 99 in "Read measured value block" mode.
• ◆ After selecting the display group 99 (whether in "Basic setting" or "Read measured value block" mode), it is possible to switch back and forth between the functions 04 "Basic setting" and 08 "Read measured value block" by pressing the keys 4 or 8 on V.A.G 1551.
• ◆ On leaving function 04 "Basic setting", the Lambda control is automatically re-activated.
• ◆ Connector for Bank 1, Lambda probe 1 (G39) and Lambda probe heating (Z19): 4-pin/black
• ◆ Connector for Bank 2, Lambda probe 1 (G108) and Lambda probe heating (Z28): 4-pin/black

Test requirements:

• ● Test drive performed and fault memory not erased.
• ● Coolant temperature at least 80 oC.

Functional check

• ‒ Connect up vehicle diagnosis, measurement and information system VAS 5051 or fault reader V.A.G 1551 and select engine electronics control unit with "Address word" 01 .
  When doing this the engine must be running at idle speed

• ‒ Enter "04" to select "Start basic setting" and confirm with Q key.

Note:

During basic setting, the solenoid valve for the active carbon canister (valve -N80) is closed and the air conditioning compressor is switched off.

• ‒ Enter "030" to select "Display Group 030" and confirm entry with the Q key.

• ‒ Check Lambda probe status in display zone 1.

Note:

The "Lambda probe status" indicates the condition of the Lambda control and the Lambda probes.

Significance of 3-digit readout of display group 030

Checking Lambda probe learned values and Lambda control

• ‒ Press Ckey.
• ‒ Enter "032" to select "Display Group 032" and confirm entry with the Q key.

• ‒ Check Lambda control
  (display zones 1 to 4):

• ‒ Press C-key.
• ‒ Enter "033" to select "Display Group 033" and confirm entry with the Q key.

• ‒ Check Lambda control
  (display zones 1 to 4):

Continuation

If the specified result is not achieved in display zone 1 or display zone 3, or if the value does not fluctuate by at least 2%:

• ‒ Test drive vehicle in order to free Lambda from any possible residues and repeat the test.

If the specified result is not achieved in display zone 1 or display zone 3, or if the value does not fluctuate by at least 2%, even after the test drive:

• ‒ Check basic voltage => Page 24-89
• ‒ Check the Lambda probe heating
  => Page 24-94.

Interpreting display group 032

Interpreting display group 032

Interpreting display group 033

Checking basic voltage

Notes:

• ◆ → Connector -arrow- for bank 1 Lambda probe 1 -G39 and Lambda probe heating -Z19: 4-pin/black

• ◆ → connector -arrow- for bank 2 Lambda probe 1 -G108 and Lambda probe heating -Z28: 4-pin/black
• ◆ To gain access to this connector screw out coolant expansion tank bolts and swivel expansion tank aside. Fuel hoses remain connected.

• ‒ Disconnect 4-pin connector to relevant Lambda probe.

• ‒ → Connect the multimeter for voltage measurement range between contact 3 and contact 4.
• ‒ Switch on the ignition.
• ‒ Specified value: 0.400 ... 0.500 V
• ‒ Switch off ignition.

If the specified value is not attained:

• ‒ Check the Lambda probe lines
  => Bank 1 Page 24-92

Checking Lambda probe wiring for Bank 1, Lambda probe 1

• ‒ Disconnect 4- pin connector (black) to Bank 1, Lambda probe 1 (G39).
• ‒ Connect the V.A.G 1598/31 test box to wiring harness leading to engine control unit; the engine control unit should not be connected => Page 24-20.

• ‒ → Test for open circuit in the following wiring connections:

• ‒ Rectify open circuit, if necessary
• ‒ Check for shorts between the two lines.
• ‒ Test screen wiring for short to Lambda probe wiring.

If no wiring fault is detected:

• ‒ Replace engine control unit => Page 24-23.

Checking Lambda probe wiring for Bank 2, Lambda probe 1

• ‒ Disconnect 4- pin connector (black) to Bank 2, Lambda probe 1 (G39).
• ‒ Connect the V.A.G 1598/31 test box to wiring harness leading to engine control unit; the engine control unit should not be connected => Page 24-20.

• ‒ → Test for open circuit in the following wiring connections:

• ‒ Rectify open circuit, if necessary
• ‒ Check for shorts between the two lines.

• ‒ → Test screen wiring for short to Lambda probe wiring.

If no wiring fault is detected:

• ‒ Replace engine control unit => Page 24-23.