SEAT Workshop Service and Repair Manuals

Note:

If the Motronic control unit (J220) and/or throttle valve control part (J338) are replaced the basic setting must be performed .

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
• ◆ Test box V.A.G 1598/18
• ◆ Hand multimeter V.A.G 1526 or multimeter V.A.G 1715
• ◆ Adapter set V.A.G 1594
• ◆ Current flow diagram

Checking voltage supply

Test conditions

• ● Battery voltage at least 11.5 V

• ‒ → Separate 8 pin connector to throttle valve control part -arrow-.

• ‒ → Connect multimeter to measure voltage at contacts 4+7 of connector.
• ‒ Switch on ignition.
      Specification: min. 4.5 V
• ‒ Connect multimeter to measure voltage at contacts 3+7 of connector.
      Specification: At least 11.5 V
• ‒ Switch off ignition

If the specifications are not attained:

• ‒ Remove dash panel insert:

=> Electrical system; Repair group 90

• ‒ → Connect test box V.A.G 1598/18 to control unit wiring loom.

• ‒ → Check wiring between test box and 8 pin connector for open circuit according to current flow diagram.
      Contact 3+socket 10
      Contact 4+socket 41
      Contact 7+socket 33
      Wire resistance: Max. 1.5 ω
• ‒ Check wiring at 8 pin connector for short to one another.
      Contact 4+socket 33
      Contact 7+socket 10
      Contact 7+socket 41
      Specification: ∞ω

If no wiring fault is detected:

• ‒ Reconnect connector.
• ‒ Renew Motronic control unit (J220)
  => Page 24-8, item 2.

Checking idling switch

Test conditions

• ● Throttle cable adjustment OK, checking:

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

• ‒ Connect fault reader V.A.G 1551 (V.A.G 1552) and select engine electronics control unit (address word 01); carry out selection at idling.
  => Page 01-4

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

• ‒ Input 05 for "Display group number" and confirm with Q.

• ‒ Check operating mode of idling switch in display zone 4.

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

If the specification is not attained:

• ‒ Press ⇒ key.

• ‒ Input 06 for "End output" and confirm with Q.
• ‒ Switch off ignition
• ‒ Remove dash panel insert:

=> Electrical system; Repair group 90

• ‒ → Connect test box V.A.G 1598/18 to control unit wiring loom.
• ‒ With throttle valve closed connect multimeter to measure resistance at test box sockets 10+33.
      Specification: max. 1.5 ω

• ‒ Slowly open throttle valve.
      Specification: ∞ω

If the specifications are not attained:

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

• ‒ → Check wiring between test box and 8 pin connector for open circuit according to current flow diagram.
      Contact 3+socket 10
      Contact 7+socket 33
      Wire resistance: Max. 1.5 ω
• ‒ Check wiring at 8 pin connector for short to one another.
      Contact 7+socket 10
      Specification: ∞ω

If no wiring fault is detected:

• ‒ Replace throttle valve control part (J338)
  , item 9.

Checking throttle valve positioner and throttle valve positioner potentiometer

Test conditions

• ● Coolant temperature at least 80 °C

Test sequence

• ‒ Connect fault reader V.A.G 1551 (V.A.G 1552) and select engine electronics control unit (address word 01); carry out selection at idling.
  => Page 01-4

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

• ‒ Input 01 for "Display group number" and confirm with Q.

Only continue with the test when

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

• ‒ Press C key.
• ‒ Input 06 for "Display group number" and confirm with Q.

• ‒ Check throttle valve positioner duty cycle at idling stop in display zone 3.
      Specification: 65...80 %

If the specification is not attained:

• ‒ Press ⇒ key.
• ‒ Input 06 for "End output" and confirm with Q.
• ‒ Switch off ignition
• ‒ Remove dash panel insert

=> Electrical system; Repair group 90

• ‒ → Connect test box V.A.G 1598/18 to control unit wiring loom.
• ‒ With throttle valve closed connect multimeter to measure resistance at test box sockets 27+53.
      Specification: 3...200 ω

If the specification is not attained:

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

• ‒ Check wiring between test box and 8 pin connector for open circuit according to current flow diagram.
      Contact 1+socket 27
      Contact 2+socket 53
      Contact 7+socket 33
      Contact 8+socket 62
      Wire resistance: Max. 1.5 ω
• ‒ → Check wiring at 8 pin connector for short to one another.
      Contact 1+socket 53
      Contact 1+socket 62
      Contact 1+socket 33
      Contact 2+socket 62
      Contact 2+socket 33
      Contact 7+socket 62
      Specification: ∞ω

If no wiring fault is detected:

• ‒ Replace throttle valve control part (J338)
  , item 9.

Checking throttle valve potentiometer

• ‒ Connect fault reader V.A.G 1551 (V.A.G 1552) and select engine electronics control unit (address word 01); carry out selection with ignition switched on.
  => Page 01-4

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

• ‒ Enter 03 for "Display group number" and confirm with Q.

• ‒ Read-off throttle valve angle in display zone 3.
      Specification: 2...8 <°
• ‒ Slowly open throttle valve fully and observe angle displayed in display zone 3.
  The figure must increase uniformly over
      the complete range.
• ‒ Press ⇒ key.
• ‒ Input 06 for "End output" and confirm with Q.
• ‒ Switch off ignition

Notes:

• ◆ If with the throttle valve closeda value of 0<°is displayedin display zone 3,perform basic setting of throttle valve control part (J338) and then repeat check.
• ◆ The displayed figure is dependent on the tolerances of the throttle valve potentiometer and does not correspond to the actual opening angle. The maximum permissible displayed figure is 86 <°.

If the figure does not increase uniformly:

• ‒ Replace throttle valve control part (J338)
  , item 9.

If the display shows constant 2 <°:

• ‒ Remove dash panel insert:

=> Electrical system; Repair group 90

• ‒ → Connect test box V.A.G 1598/18 to control unit wiring loom.
• ‒ Check wire for short to earth.
      Sockets 1+40
      Specification: ∞ω
• ‒ Switch on ignition.
• ‒ Check wire for short to positive, to do this connect multimeter to measure voltage at test box sockets 1+40
      note voltage if voltage present
• ‒ Switch off ignition

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

Continuation if voltage is present:

If voltage of about 5 V was present:

• ‒ Switch on ignition.

• ‒ → Check wiring at 8 pin connector contacts 4+5 for short to one another according to current flow diagram.

If the voltage was approx. 11.5 V:

• ‒ Check wire at 8 pin connector contact 5 for short to battery positive according to current flow diagram.

Continuation if no voltage is present:

• ‒ → Check wiring between test box and 8 pin connector for open circuit according to current flow diagram.
      Contact 5+socket 40
      Wire resistance: Max. 1.5 ω

If no wiring fault is detected:

• ‒ Replace throttle valve control part (J338)
  , item 9.