Volkswagen Workshop Service and Repair Manuals

Note:

Check whether Motronic control unit (J220) recognises the engine operating mode (idling, overrun, part throttle, enrichment, full throttle).

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

• ● Coolant temperature at least 80 °C
• ● Throttle cable adjustment OK, checking:

=> Repair group 20; Removing and installing parts of fuel supply system; Adjusting throttle mechanism

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 .)

• ‒ 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-

• ‒ Press C key.
• ‒ Press keys 0, 0 and 5 for "Display group number 5" and confirm entry with Q key.

Display for operating modes in display zone 4:

• ◆ Idling:

• As long as the engine is running at idling speed idling must be displayed
       Display: Idling

• ◆ Overrun mode:

• ‒ Increase engine speed to above 3000 rpm.
• ‒ Close throttle valve abruptly.

• As long as the engine speed is above 1400 rpm overrun must be displayed
       Display: Overrun

Note:

Below 1400 rpm idling speed will be recognised.

• ◆ Part throttle:

• ‒ Rev up evenly.

• As long as the engine is being revved up evenly, part throttle must be displayed
       Display: Part throt.

• ◆ Enrichment:

• ‒ Quickly increase engine speed.

• Enrichment must be displayed briefly
       Display: Enrichment

• ◆ Full throttle:

Note:

A test drive may have to be performed to show "Full throttle" in display.

A 2nd person is required when performing a test drive.

• ‒ Floor accelerator pedal (onto throttle valve stop).

• As long as the engine is at full throttle, full throttle must be displayed
       Display: Full throttle

• ‒ Press the ⇒key.
• ‒ Press keys 0 and 6 for the "End output" function and confirm input with the Q key.

If the specifications are not attained:

• ‒ Interrogate and erase fault memory, eliminate faults if necessary => Page 01-10 .
• ‒ Check accelerator mechanism for ease of operation.
• ‒ Check throttle valve potentiometer
  => Page 24-33 , checking throttle valve control part.