Volkswagen Workshop Service and Repair Manuals

Functional check

• ‒ Functional check , final control diagnosis.

Checking regulation

Special tools, testers and auxiliary items

• ◆ Fault reader V.A.G 1551 with cable V.A.G 1551/3

Test sequence

• ‒ Start engine and run at idling speed.
• ‒ Connect fault reader V.A.G 1551 and select engine electronics control unit (address word 01); selection is carried out with engine idling .

• ‒ Input 08 for "Read measured value block" function and confirm with Q.

• ‒ Input 01 for display group 01 and confirm with Q.

Note:

If something different is indicated on the display:

=> Fault reader operating instructions

Do not continue with check until engine temperature exceeds 80 °C (display field 2).

• ‒ Briefly increase engine speed (rev. up accelerator) and then allow engine to run at idling speed for 2 minutes.
• ‒ Press C button
• ‒ Input 05 for display group 05 and confirm with Q.

• ‒ Read and note duty cycle in zone 3.

• ‒ → Pull connector -1- off coolant temperature sender -2-. The duty cycle must
       increase
  and drop again to the original value.

Note:

Test can only be repeated after the fault memory has been erased.

• ‒ Reconnect coolant temperature sender connector.
• ‒ Press ⇒ button.
• ‒ Input 02 for "Interrogate fault memory" function and confirm with Q.
• ‒ Press ⇒button until all faults still stored have been displayed and the display reads:
• ‒ Input 05 for "Erase fault memory" function and confirm with Q.
  
• ‒ Press ⇒ button.
• ‒ Input 06 for "End output" and confirm with Q.