Volkswagen Workshop Service and Repair Manuals

Notes:

• ◆ Idling speed, ignition timing and CO content not adjustable.
• ◆ The idling speed is regulated to specification by the throttle valve positioner in conjunction with the DIS function.
• ◆ CO content regulated by Lambda regulation. Faults in Lambda control are detected in self-diagnosis and stored in fault memory.

Special tools, testers, measuring instruments and auxiliary items required

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

Check conditions

• ● Engine oil temperature at least 80 °C
• ● Electrical consumers switched off
• ● Air conditioner switched off
• ● Accelerator cable adjustment OK

=> Repair group 20, removing and installing parts of the fuel supply system, adjusting accelerator cable

Test sequence

• ‒ Connect fault reader V.A.G 1551 (V.A.G 1552) and select engine electronics control unit with the "Address word" 01. When doing this the engine must be running at idling speed.
  (Connecting fault reader and selecting engine electronics control unit .)
• ‒ Interrogate fault memory, if necessary, repair fault and then erase fault memory.
  => Page 01-10 , interrogating and erasing fault memory
• ‒ Then:
• ‒ Leave fault reader V.A.G 1551 connected.
• ‒ Continue running engine at idling speed.

• ‒ Press keys 0 and 8 for the function "Read measured value block" and confirm entry with Q key.

• ‒ Press keys 0, 0 and 1 for "Display group number 1" and confirm entry with Q key.

Only continue with the test when

• ● The coolant temperature is above 80 °C
  -Display zone 2-

• ‒ Briefly increase engine speed (rev-up) and then allow engine to run at idling speed for 2 minutes.
• ‒ Press C key.

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

• ‒ Check idling speed in display zone 1.
       Specification: 650...750 rpm1)

     1)     Up-to-date specifications:

=> Exhaust emissions test binder

• ‒ Check throttle valve angle for idling in display zone 3.
       Specification: Max. 8 <°
• ‒ Afterwards check ignition angle (at idling speed) in display zone 4.
       average specification: 6° BTDC.
• ‒ Press ⇒key.
• ‒ Press keys 0 and 6 for the function "End output" and confirm entry with the Q key.
• ‒ Switch off ignition.

If the specification is not obtained:

• ‒ Match engine control unit to throttle valve control part => Page 24-108
• ‒ Carry out road test, interrogate fault memory again and repeat idling check.

If the specifications are again not attained:

• ‒ Check throttle valve control part
  => Page 24-33 .