Audi Workshop Service and Repair Manuals

Special tools, workshop equipment, testers, measuring instruments and other items required

• ◆ Fault reader V.A.G 1551 (or vehicle system tester V.A.G 1552) with wire V.A.G 1551/3

• ◆ → Engine-speed setting tool V.A.G 1788/10

Test requirements

• ● Vehicle stationary
• ● On vehicles with automatic gearbox, selector lever must be set to "P" or "N"
• ● All electr. loads such as lights and heated rear window switched off
• ● Intake-air temperature lower than 60°C
  =>Display group 04, display zone 4
• ● Coolant temperature must be at least 80 °C =>Display group 04, display zone 3.

Sequence of operations

• ‒ Connect fault reader V.A.G 1551 (V.A.G 1552). Then start engine and select engine control unit with "Address word" 01.
  (Connecting fault reader and selecting engine control unit)

Step 1: Interrogating fault memory

• ‒ Press keys 0 and 2 for "Interrogate fault memory" function and confirm entry with Q key.

If a fault has been stored:

• ‒ Use fault table to remedy faults printed out.

If no fault has been stored:

• ‒ Press ⇒key.

Step 2: Erasing fault memory

• ‒ Press keys 0 and 5 for "Erase fault memory" function and confirm entry with Q key.

Note:

The readiness code is reset/erased whenever the fault memory is erased.

Note:

Fault memory is not erased if ignition is switched off between "Interrogating fault memory" and "Erasing fault memory".

• ‒ Press ⇒key.

Note:

• ◆ Engine must not be switched off again during the sequence of operations.

Step 3: Diagnosis of fuel supply system and continuous-action lambda probe upstream of catalytic converter

Note:

This diagnostic function is only concluded if there are no faults relating to the lambda probes and fuel supply system.

• ‒ Press keys 0 and 4 for "Start basic setting" function and confirm entry with Q key.

• ‒ Press keys 2, 0 and 2 for "Display group number 202" and confirm entry with Q key.

• ‒ Maintain engine speed at 1400...1800 rpm until display in
      zones 2 and 3 switches from "Test OFF" to "Test ON".

• ‒ Continue to maintain engine speed at 1400...1800 rpm until
      display zones 2 and 3 show specification "Syst. OK".

Note:

Several minutes may be required for display to switch from "Test ON" to "Syst. OK".

If readings do not match specifications:

• ‒ Interrogate fault memory => Page 01-14.

If readings match specifications:

• ‒ Press C key.

Step 4: Diagnosis of activated charcoal filter system (fuel tank breather system)

• ‒ Press keys 0 and 4 for "Start basic setting" function and confirm entry with Q key.

• ‒ Press keys 0, 7 and 0 for "Display group number 70" and confirm entry with Q key.

Note:

Do not press clutch and brake.

If diagnosis is initiated by engine control unit, display in zone 4 switches from "Test OFF" to "Test ON".

• ‒ Leave engine idling until
      display zone 4 shows specification "TEV OK".

If display is not as described:

• ‒ Interrogate fault memory => Page 01-14.
• ‒ Give roughly 3 bursts of throttle and repeat diagnosis.

If display is as described:

• ‒ Press C key.

Step 5: Diagnosis of secondary air system

• ‒ Press keys 0 and 4 for "Start basic setting" function and confirm entry with Q key.

• ‒ Press keys 0, 7 and 7 for "Display group number 77" and confirm entry with Q key.

Note:

Do not press clutch and brake.

If diagnosis is initiated by engine control unit, display in zone 4 switches from "Test OFF" to "Test ON".

• ‒ Leave engine idling until
       display zone 4 shows specification "Syst. OK".

If display is not as described:

• ‒ Interrogate fault memory => Page 01-14.

If display is as described:

• ‒ Press C key.

Step 6: Diagnosis of catalytic converter

Note:

This diagnostic function is only concluded if there are no faults relating to the lambda probes and activated charcoal filter system.

• ‒ Press keys 0 and 4 for "Start basic setting" function and confirm entry with Q key.

• ‒ Press keys 0, 4 and 6 for "Display group number 46" and confirm entry with Q key.

• ‒ Maintain engine speed at 1800...2200 rpm until display in
      zone 4 switches from "Test OFF" to "Test ON". Catalytic converter temperature in
      display zone 2 must be at least 300 °C.

• ‒ Continue to maintain engine speed at 1800...2200 rpm until
      display zone 4 shows specification "Cat. B1 OK".

Note:

Several minutes may be required for display to switch from "Test ON" to "Cat. B1 OK".

If readings do not match specifications:

• ‒ Interrogate fault memory => Page 01-14.

If readings match specifications:

• ‒ Press C key.

Step 7: Diagnosis of condition of lambda probe downstream of catalytic converter

• ‒ Press keys 0, 3 and 6 for "Display group number 36" and confirm entry with Q key.

• ‒ Press ⇒key.

If diagnosis is initiated by engine control unit, display in zone 2 switches from "Test OFF" to "Test ON".

• ‒ Leave engine idling until
      display zone 2 shows specification "B1 S2 OK".

Note:

Several minutes may be required for display to switch from "Test ON" to "B1 S2 OK".

If readings do not match specifications:

• ‒ Interrogate fault memory => Page 01-14.

If readings match specifications:

• ‒ Press C key.

Step 8: Diagnosis of ageing of lambda probe downstream of catalytic converter

Note:

This diagnostic function is only concluded if there are no faults relating to the lambda probes.

• ‒ Press keys 0 and 4 for "Start basic setting" function and confirm entry with Q key.

• ‒ Press keys 0, 4 and 3 for "Display group number 43" and confirm entry with Q key.

• ‒ Maintain engine speed at 1800...2200 rpm until display in
      zone 4 switches from "Test OFF" to "Test ON". Catalytic converter temperature in
  display zone 2 must be at least 350 °C.

• ‒ Continue to maintain engine speed at 1800...2200 rpm until
      display zone 4 shows specification "B1 S2 OK".

Note:

Several minutes may be required for display to switch from "Test ON" to "Syst. OK".

If readings do not match specifications:

• ‒ Interrogate fault memory => Page 01-14.

If readings match specifications:

• ‒ Press ⇒key.
• ‒ Press keys 0 and 6 for "End output" function and confirm entry with Q key.
• ‒ Read out readiness code => Page 01-58.