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Measured value blocks > < Final control diagnosis

Golf Mk4

Performing final control diagnosis
Performing final control diagnosis
Special tools and workshop equipment required
t  Fault reader -V.A.G 1551- with diagnosis lead -V.A.G 1551/3-
Test requirements for vehicles with air conditioning system
l  Vehicle at room temperature (warmer than + 15 °C)
l  Air conditioning system switched on
l  Select lowest temperature and highest blower speed
The final control diagnosis activates the following components in the stated sequence:
1. Commencement of injection valve -N108-
2. Exhaust gas recirculation valve -N18-
3. A/C compressor intervention
4. Engine codes AGR; AHF and ALH: Fuel shutoff valve -N109-
Engine codes AGP, AQM: Intake manifold flap motor -V157-
5. Engine codes AGR; AHF and ALH: Solenoid valve for charge pressure control -N75-
Engine codes AGP, AQM: Fuel shutoff valve -N109-
6. Glow plug relay -J52-
7. Glow period warning lamp -K29-
8. Relay for low heater output -J359- (only on vehicles with manual gearbox)
9. Relay for high heater output -J360- (only on vehicles with manual gearbox)
10. Only engine code AHF: Fan relay -J323-
  Note
t  Activation of individual control elements is limited to 30 sec. but can be stopped at any time by pressing the → button.
t  The ignition must be switched off before repeating the final control diagnosis.
Procedure
–  Connect fault reader -V.A.G 1551- or vehicle system tester -V.A.G 1552- and select control unit for engine electronics with “address word 01”. Engine must be idling. (Connecting fault reader and selecting engine electronics control unit → Chapter.)
   
Indicated on display:
–  Operate fault reader taking into account the information on the display:
–  Press keys 0 and 3 for function “Final control diagnosis”.
  
Rapid data transfer                 HELP
Select function XX
Indicated on display:
–  Confirm entry with Q key.
  
Rapid data transfer                    Q
03-Final control diagnosis
Indicated on display:
Actuation of the valve results in a clearly noticeable audible change in the combustion noise (pinking noise).
If no change in the combustion noise is heard:
–  Check injection timing control range → Chapter
–  Press → button.
  
Final control diagnosis               ->
Commencement of injection valve N108
Indicated on display:
The valve must click.
  Note
The valve clicking cannot be heard because of engine noises and can therefore only be felt by touch.
If the valve does not click:
–  Check exhaust gas recirculation → 4-cyl. diesel engine, mechanics; Rep. Gr.26
–  Press → button.
  
Final control diagnosis               ->
Exhaust gas recirculation valve N18
Indicated on display:
Air conditioner compressor switch-off is checked.
The test step is also recalled on vehicles without air conditioner system.
The air conditioner compressor must stop within 5 seconds (visual check), and then start approx. every 5 seconds and stop again.
If the conditioner compressor is not switched off:
–  Check signals from/to air conditioning system → Chapter
–  Press → button.
  
Final control diagnosis               ->
Conditioner compressor interruption
Indicated on display for engine codes AGR, AHF and ALH:
The engine must stop.
If the engine does not stop:
–  Switch off ignition.
–  Unscrew fuel shut-off valve -N109- and remove any metal particles and dirt.
–  Repeat final control diagnosis, if the engine still does not stop, replace fuel shut-off valve -N109-.
–  Continue final control diagnosis with engine stationary and ignition switched on.
–  Press → button.
  
Final control diagnosis               ->
Fuel shut-off valve N109
Indicated on display for engine codes AGP, AQM:
Activation of the intake manifold flap motor -V157- changes the combustion noise (control motor opens and closes intake manifold flap).
If no changes in the combustion noise can be heard:
–  Check intake manifold flap motor -V157- → Chapter.
–  Press → button.
  
Final control diagnosis               ->
Intake manifold flap motor V157
Indicated on display for engine codes AGP, AQM:
The engine must stop.
If the engine does not stop:
–  Switch off ignition.
–  Unscrew fuel shut-off valve -N109- and remove any metal particles and dirt.
–  Repeat final control diagnosis. If the engine still does not stop, renew fuel shut-off valve -N109- → Chapter.
–  Continue final control diagnosis with engine stationary and ignition switched on.
–  Press → button.
  
Final control diagnosis               ->
Fuel shut-off valve N109
Indicated on display for engine codes AGR, AHF and ALH:
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:
–  Check charge pressure control solenoid -N75- → 4-cyl. diesel engine, mechanics; Rep. Gr.21
–  Press → button.
Continuation for all engine codes
  
Final control diagnosis               ->
Charge press. cont. solen. val. N75
Indicated on display:
The relay must click.
Switching on and off the relay can also be observed as the interior light becomes brighter and darker as a result of the glow plug high power consumption.
If the relay does not click:
–  Check glow plug relay -J52-: → Current flow diagrams, Electrical fault finding and Fitting locations
–  Press → button.
  
Final control diagnosis               ->
Glow plug relay J52
Indicated on display:
The warning lamp must flash.
Warning lamp does not flash:
–  Check glow period warning lamp -K29-: → Current flow diagrams, Electrical fault finding and Fitting locations
–  Press → button.
  
Final control diagnosis               ->
Glow period warning lamp K29
Indicated on display:
The relay must click.
If the relay does not click:
–  Check relay for low heater output -J359-: → Current flow diagrams, Electrical fault finding and Fitting locations
–  Press → button.
  
Final control diagnosis               ->
Relay for low heater output J359
Indicated on display:
The relay must click.
If the relay does not click:
–  Check relay for high heater output -J360-: → Current flow diagrams, Electrical fault finding and Fitting locations
–  Press → button.
  
Final control diagnosis               ->
Relay for high heater output J360
Indicated on display for engine code AHF:
The fan must run every 5 seconds and then stop again.
If the fan does not run:
–  Check fan relay -J323-: → Current flow diagrams, Electrical fault finding and Fitting locations
Continuation for all engine codes
–  Press → button.
  
Final control diagnosis               ->
Fan relay J323
Indicated on display:
–  Press keys 0 and 6 for function “End data transfer” and confirm entry with Q key.
–  Switch off ignition.
  
Rapid data transfer                 HELP
Select function XX

Measured value blocks > < Final control diagnosis