Audi Workshop Service and Repair Manuals

Test requirements for vehicles with air -conditioners

• ● Vehicle at room temperature (warmer than + 15 °C)
• ● Air conditioner switched on
• ● Lowest temperature and fastest fan speed selected

The final control diagnosis activates the following components in the stated order:

1. Injection start valve (N108)

2. Valve for exhaust gas recirculation (N18)

3. Air conditioner compressor cut-in

4. Fuel cut-off valve (N109)

5. Solenoid valve for boost pressure limitation (N75)

6. Glow plug relay (J52)

7. Pre-glow time warning lamp (K29)

8. Low heating output relay (J359)

• (vehicles with manual gearboxes only)

9. High heating output relay (J360)

• (vehicles with manual gearboxes only)

10. Blower relay (J323)

• (only vehicles with engine code AFN)

• ‒ Connect fault reader V.A.G 1551 (V.A.G 1552) and select the engine electronics control unit using "Address word" 01. When doing this the engine must be running at idling speed.
  (Connecting fault reader and selecting engine electronics control unit .)

• ‒ Press keys 0 and 3 for "Final control diagnosis" function

• ‒ Confirm input with Q key.

• Valve actuation has a considerable effect on combustion noise (pre ignition).

If no change in the combustion noise is heard:

• ‒ Check the injection timing control range
  .
• ‒ Press ⇒key.

• The injector valve should click.

Notes:

• ◆ Due to the engine noise, the clicking of the valve is not audible and therefore may only be detected by feeling.
• ◆ The piston movement of the mechanical exhaust gas recirculation valve is clearly visible in the side slot.

If the injector does not click:

• ‒ Testing exhaust gas recirculation valve

=> 4-cyl. Diesel Direct Injection System (TDI), Mechanical Components; Repair group 26; Check exhaust gas recirculation system; Check exhaust gas recirculation valve

• ‒ Press ⇒key.

• Check the air conditioner compressor shutoff.
• This test step is also invoked for vehicles without air conditioners.
• The conditioner compressor must stop within 5 secs. (visual check) then start approx. every 5 secs. and then stop again.

If the conditioner compressor is not switched off:

• ‒ Checking the air conditioner compressor shutoff
  .
• ‒ Press ⇒key.

• The engine must stop.

If the engine does not stop:

• ‒ Switch ignition off.
• ‒ Unscrew the fuel cut-off valve and remove any metallic parts or dirt

• ‒ Repeat final control diagnosis and if the engine will still not stop, replace the fuel cut off valve.
• ‒ Press ⇒key.

• The solenoid valve must click.

Note:

The clicking of the valve is difficult to hear and is therefore best checked by touch.

If the solenoid valve does not click:

• ‒ Test boost pressure control solenoid valve

=> 4-cyl. Diesel Direct Injection System (TDI), Mechanical Components; Repair group 21; Check boost pressure system; Check solenoid valve for boost pressure control

• ‒ Press ⇒key.

• The relay must click.
• Fitting location: Central electrics, relay position 4

• Due to the high current consumption, the switching on and off of the relay may also be observed from the interior light becoming brighter and darker.

If the relay does not click:

• ‒ Check the glow plug relay:

=> Current Flow Diagrams, Electrical Fault-finding and Fitting Locations binder

• ‒ Press ⇒key.

• The warning lamp must blink.

Warning lamp does not blink:

• ‒ Check glow plug warning lamp => Page 28-3
• ‒ Press ⇒key.

• (vehicles with manual gearboxes only)
• The relay must click.
• Fitting location: Electronics box in the plenum chamber

If the relay does not click:

• ‒ Test low heating output relay:

=> Current Flow Diagrams, Electrical Fault-finding and Fitting Locations binder

• ‒ Press ⇒key.

• (vehicles with manual gearboxes only)
• The relay must click.
• Fitting location: Electronics box in the plenum chamber

If the relay does not click:

• ‒ Test high heating output relay

=> Current Flow Diagrams, Electrical Fault-finding and Fitting Locations binder

• ‒ Press ⇒key.

• The radiator fan should come on and then switch off again.
• (only vehicles with engine code AFN)

Note:

The radiator fan may also be activated by the thermoswitch, the automatic gearbox or the air conditioner. When performing the final control diagnosis, ensure that the fan has not been actuated for this reason.

• ‒ If necessary, allow engine to cool down.

If the radiator fan is not activated:

• ‒ Test radiator fan actuation

=> Current Flow Diagrams, Electrical Fault-finding and Fitting Locations binder

• ‒ Press keys 0 and 6 for the "End output" function and press the Q key to confirm entry.