SEAT Workshop Service and Repair Manuals

Components of throttle valve control part (J338):
Throttle valve drive (G186), angle sender 1 for throttle valve drive (G187) and angle sender 2 for throttle valve drive (G188).

Note:

If the throttle valve control part is replaced, the new control part must without fail be adapted to the engine control unit .

On vehicles fitted with an automatic gearbox the gearbox control unit must also be adapted:

=> Self-diagnosis for automatic gearbox 099; 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 1598/31
• ◆ Hand multimeter V.A.G 1526 or multimeter V.A.G 1715
• ◆ Adapter set V.A.G 1594
• ◆ Current flow diagram

Check conditions

• ● The fault memory has been interrogated => Page 01-17, interrogating fault memory of engine control unit.
• ● All electrical consumers, e.g. lights and rear window heating must be switched off
• ● If the vehicle is equipped with an air conditioning system, this must be switched off.
• ● The battery voltage must be at least 11.5 V.
• ● Throttle valve not damaged or dirty.
• ● Coolant temperature must be at least 80 °C, =>display group 04, display zone 3.

Test sequence

• ‒ Connect the fault reader V.A.G 1551 (V.A.G 1552). Then switch ignition on and select engine control unit with the "Address word" 01.
  (Connecting fault reader and selecting engine control unit => Page 01-9.)

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

• ‒ Press keys 0, 6 and 2 for the "Display group number 62" and confirm entry with Q key.

• ‒ Check throttle valve angle from sender 1 (G187) at idling stop in display zone 1
      Specification: 3...25 %
• ‒ Check throttle valve angle from sender 2 (G188) at idling stop in display zone 2.
      Specification: 97...75 %
• ‒ Depress accelerator slowly to full throttle position and observe angles displayed in display zones 1 and 2:

• The percentage indicated in display zone 1 must increase evenly, although the tolerance range 3...93 % will not be fully exploited.
• The percentage figure in display zone 2 must decrease evenly, although the tolerance range 97...3 % will not be fully exploited.

Notes:

• ◆ The reason why the display in display zone 1 increases and the display in display zone 2 decreases is because the potentiometers (angle senders) in the throttle valve control part run in opposite directions.
• ◆ The percentage indicated in display zones 1 and 2 must always total approx. 100 %.
• ◆ This means that the voltage of one angle sender moves towards 5 volts. (The more the throttle valve is opened the higher the voltage; percentage figure increases).
• ◆ Whilst the voltage of angle sender 2 decreases from 5 volts towards 0 volts. (The more the throttle valve is opened the lower the voltage; percentage figure decreases).

If the displays do not indicate as described:

• ‒ Press ⇒key.

• ‒ Press keys 0 and 6 for the function "End output" and confirm entry with the Q key.
• ‒ Switch off ignition.
• ‒ Remove battery.
• ‒ → Connect test box V.A.G 1598/31 to control unit wiring harness. The engine control unit remains disconnected.
• ‒ Measure resistance of throttle valve drive between test box sockets 117 + 118
      Specification: 3...200 ω

If the specification is not obtained:

• ‒ Replace throttle valve control part (J338).
• ‒ Adapt engine control unit again => Page 24-111

If the specification is obtained:

• ‒ Check voltage supply of throttle valve control part and wiring to control unit => Page 24-43.
• ‒ Check the accelerator pedal position sender.

=> Repair group 20; Electronic engine output regulation (electronic accelerator (EPC)); Checking accelerator pedal position sender

If the voltage supply and wiring is OK:

• ‒ Renew engine control unit => Page 24-108.

Checking voltage supply and wiring to control unit

• ‒ → Pull the 6-pin connector -2- off the throttle valve control part -1-.

• ‒ → Connect multimeter to measure voltage at contacts 2 and 6.
• ‒ Switch on ignition.
      Specification: min. 4.5 V
• ‒ Switch off ignition.

• ‒ → Connect multimeter to measure voltage at connector contact 2 and earth.
• ‒ Switch on ignition.
      Specification: min. 4.5 V
• ‒ Switch off ignition.

If the specifications are not attained:

• ‒ Remove battery.
• ‒ → Connect test box V.A.G 1598/31 to control unit wiring harness. The engine control unit remains disconnected.

• ‒ → Check wiring for open circuit between test box socket and connector using current flow diagram:
      Contact 1 and test box socket 92
      Contact 2 and test box socket 83
      Contact 3 and test box socket 117
      Contact 4 and test box socket 84
      Contact 5 and test box socket 118
      Contact 6 and test box socket 91
      Wire resistance: max. 1.5 ω
• ‒ Additionally check wiring for short to one another, and for short to battery positive or earth.
  Specification: ∞ω

Note:

When servicing connectors only gold-plated contacts are to be used.

If no fault is detected in the wiring:

• ‒ Check engine control unit voltage supply => Page 24-104.