Volkswagen Workshop Service and Repair Manuals

Components of the throttle valve control part (J338):
Throttle valve positioner (V60), throttle valve positioner potentiometer (G88), throttle valve potentiometer (G69) and idling switch (F60)

Note:

If the throttle valve control part is replaced, the following must be carried out:

• ◆ Match engine control unit to the throttle valve control part
• ◆ On vehicles with automatic gearbox: Match the gearbox control unit

=> Automatic gearbox 01M self-diagnosis; Repair group 01; performing self-diagnosis; initiating basic setting

Special tools, workshop equipment, 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
• ◆ Test box V.A.G 1598/22
• ◆ Hand multimeter V.A.G 1526 or multimeter V.A.G 1715
• ◆ Adapter set V.A.G 1594
• ◆ Current flow diagram

Checking idling switch

Test sequence

• ‒ Connect fault reader V.A.G 1551 (V.A.G 1552). Start engine and select "Address word" 01 of engine control unit. When doing this the engine must be running at idling speed.
  (Connecting fault reader and selecting engine control unit => Page 01-5 .)

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

• ‒ Press keys 0, 9 and 8 for "Display group number 98" and confirm entry with Q key.

• ‒ Check the operating mode display in display zone 3.
       Display: Idling

• ‒ Slowly open throttle valve. After free travel, a stop is reached when opening throttle valve further the 4th position from left must jump to part throttle
       Display: Part throttle

Display constantly remains on one operating condition:

Continuation of check when display constantly shows part throttle

• ‒ → Pull 8 pin connector off throttle valve control part -arrow-.

• ‒ → Bridge connector contacts 3+7 with aux. cables from V.A.G 1594 and observe display.

If display jumps to idling:

• ‒ Press the ⇒key.
• ‒ Press keys 0 and 6 for the function "End output" and confirm entry with the Q key.
• ‒ Switch off ignition.
• ‒ Replace throttle valve control part
  , item 1 .

If display remains on idling:

• ‒ Press the ⇒key.
• ‒ Press keys 0 and 6 for the function "End output" and confirm entry with the Q key.
• ‒ Switch off ignition.
• ‒ Check voltage supply of throttle valve control part and wiring to control unit => Page 24-45 .

If the voltage supply and wiring is OK:

• ‒ Replace engine control unit
  => Page 24-102 .

Continuation of check when display constantly shows idling

• ‒ → Pull 8 pin connector off throttle valve control part -arrow-.

If display jumps to part throttle:

• ‒ Press the ⇒key.
• ‒ Press keys 0 and 6 for the function "End output" and confirm entry with the Q key.
• ‒ Switch off ignition.
• ‒ Replace throttle valve control part
  , item 1 .

If display remains on part throttle:

• ‒ Press the ⇒key.
• ‒ Press keys 0 and 6 for the function "End output" and confirm entry with the Q key.
• ‒ Switch off ignition.
• ‒ Check voltage supply of throttle valve control part and wiring to control unit => Page 24-45 .

If the voltage supply and wiring is OK:

• ‒ Replace engine control unit
  => Page 24-102 .

Checking throttle valve positioner and throttle valve positioner potentiometer

Test conditions

• ● Coolant temperature at least 85 °C.

Test sequence

• ‒ Connect fault reader V.A.G 1551 (V.A.G 1552). Start engine and select "Address word" 01 of engine control unit. When doing this the engine must be running at idling speed.
  (Connecting fault reader and selecting engine control unit => Page 01-5 .)

• ‒ 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.

• ‒ Check whether the coolant temperature is above 85 °C in display zone 2.
• ‒ Change to display group 98 as follows:
• ‒ Press C key.

• ‒ Press keys 0, 9 and 8 for "Display Group 98" and confirm entry by pressing Q.

• ‒ Check voltage value from throttle valve positioner sender in display zone 2. The voltage must be between
       0.500...5.000 V

If the specification is not obtained:

• ‒ Press the ⇒key.
• ‒ Press keys 0 and 6 for the function "End output" and confirm entry with the Q key.
• ‒ Switch off ignition.

• ‒ → Pull 8 pin connector off throttle valve control part -arrow-.

• ‒ → Measure throttle valve positioner resistance between connector contacts 1+2.
       Specification: 3...200 ω

If the specification is not obtained:

• ‒ Replace throttle valve control part
  , item 1 .

If the specification is attained:

• ‒ Check voltage supply of throttle valve control part and wiring to control unit => Page 24-45 .

Checking throttle valve potentiometer

Test conditions

• ● Coolant temperature at least 85 °C.

Test sequence

• ‒ Connect fault reader V.A.G 1551 (V.A.G 1552). Start engine and select "Address word" 01 of engine control unit. When doing this the engine must be running at idling speed.
  (Connecting fault reader and selecting engine control unit => Page 01-5 .)

• ‒ 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.

• ‒ Check whether the coolant temperature is above 85 °C in display zone 2.
• ‒ Change to display group 3 as follows:
       V.A.G 1551: Press key 3 twice
       V.A.G 1552: Press key ↑twice

• ‒ Read off throttle valve angle in display zone 3.
       Throttle valve in start position: 1...7<°
  
• ‒ Slowly open throttle valve slowly until fully open and observe angle display in display zone 3. The figure must increase uniformly over
  the complete range
       up to a min. 75 <°.
• ‒ Press the ⇒key.
• ‒ Press keys 0 and 6 for the function "End output" and confirm entry with the Q key.
• ‒ Switch off ignition.

Note:

The displayed figure is dependent on the tolerances of the throttle valve potentiometer and does not correspond to the actual opening angle.

If the figure does not increase uniformly:

• ‒ Replace throttle valve control part
  , item 1 .

If the display constantly shows 0 <° or is above 90 <°:

Continuation of check when display shows 0 <°:

• ‒ → Pull 8 pin connector off throttle valve control part -arrow-.

• ‒ → Bridge connector contacts 5+7 with auxiliary cables from V.A.G 1594 and observe display.

If display jumps above 90 <°:

• ‒ Press ⇒key.
• ‒ Press keys 0 and 6 for the function "End output" and confirm entry with the Q key.
• ‒ Switch off ignition.
• ‒ Replace throttle valve control part
  , item 1 .

If display remains at 0 <°:

• ‒ Press ⇒key.
• ‒ Press keys 0 and 6 for the function "End output" and confirm entry with the Q key.
• ‒ Switch off ignition.
• ‒ Check voltage supply of throttle valve control part and wiring to control unit => Page 24-45 .

If the voltage supply and wiring is OK:

• ‒ Replace engine control unit
  => Page 24-102 .

Continuation of check when display is above 90 <°:

• ‒ → Pull 8 pin connector off throttle valve control part -arrow-.

If display jumps to 0 <°:

• ‒ Press ⇒key.
• ‒ Press keys 0 and 6 for the function "End output" and confirm entry with the Q key.
• ‒ Switch off ignition.
• ‒ Replace throttle valve control part
  , item 1 .

If display remains above 90 <°:

• ‒ Press ⇒key.
• ‒ Press keys 0 and 6 for the function "End output" and confirm entry with the Q key.
• ‒ Switch off ignition.
• ‒ Check voltage supply of throttle valve control part and wiring to control unit => Page 24-45 .

If the voltage supply and wiring is OK:

• ‒ Replace engine control unit
  => Page 24-102 .

Checking voltage supply and wiring to control unit

Test conditions

• ● The battery voltage must be at least 11.5 V.

Test sequence

• ‒ → Pull 8 pin connector off throttle valve control part -arrow-.

• ‒ → Connect multimeter to measure voltage using aux. cables from V.A.G 1594 to connector contacts 4+7.
• ‒ Switch on ignition.
       Specification: min. 4.5 V
• ‒ Switch off ignition.
• ‒ Connect multimeter to measure voltage at connector contacts 3+7.
• ‒ Switch on ignition.
       Specification: min. 9.0 V
• ‒ Switch off ignition.

• ‒ Remove wiper arms and cowl panel:

=> Electrical system; Repair group 92; windscreen wiper system; removing and installing windscreen wiper system

• ‒ → Connect test box V.A.G 1598/22 to control unit wiring harness.

• ‒ → Check wiring between test box and connector for open circuit using current flow diagram.
       Contact 1+socket 66
       Contact 2+socket 59
       Contact 3+socket 69
       Contact 4+socket 64
       Contact 5+socket 75
       Contact 7+socket 67
       Contact 8+socket 74
       Wire resistance: Max. 1.5 ω
• ‒ Additionally check wires for short to one another.
       Specification: ∞ω

If no wiring fault is detected:

• ‒ Check voltage supply of engine control unit => Page 24-99 .