SEAT Workshop Service and Repair Manuals

Notes:

• ◆ Knock sensor 2 (G66) has a direct 2-pole connector and therefore no contact for the shielding in the socket.
• ◆ It is extremely important to keep to the tightening torque of 20 Nm to ensure the knock sensors perform perfectly.
• ◆ Only gold-plated contacts may be used when servicing the knock sensor connector contacts.

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

• ● Self-diagnosis must have recognized a fault on one or both knock sensors , Interrogating and erasing fault memory.
• ● Coolant temperature must be at least 85 °C, =>display group 28, display zone 3.

Checking function

• ‒ 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 .)

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

• ‒ Press keys 0, 2 and 8 for the "Display group number 28" and confirm entry with Q key.

Note:

Checking the knock sensors must be performed during a test drive because the diagnosis of the knock sensors is not activated until the engine speed exceeds 2000 rpm and the engine is loaded by more than 40 %.

• ‒ Perform a test drive and check knock control specifications on display (display zone 4)

Observe the valid safety precautions when carrying out a test drive => Page 28-8.

If the specification is attained:

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

Continuation:

If the specifications are not obtained:

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

Checking resistance of knock sensors

Knock sensor 1 (G61)

• ‒ → Separate 3-pin connector to knock sensor 1 (G61) -arrow- (on exhaust side of cylinder head).

• ‒ → Measure resistance between contacts 1+2, 1+3 and 2+3 at connection to knock sensor 1 (G61).
      Specification ∞ω

Knock sensor 2 (G66)

• ‒ → Pull 2-pin connector off knock sensor 2 -arrow- (intake side of cylinder block).

• ‒ → Now measure resistance between contacts 1+2 at connection to knock sensor 2 (G66).
      Specification: ∞ω

If the specification is not obtained:

• ‒ Replace the knock sensor/s (G61 or G66) , item 15.
• ‒ Interrogate fault memory, if necessary, repair any faults and then erase fault memory => Page 01-16, interrogating and erasing fault memory.
• ‒ Read-out the readiness code=> Page 01-64.

If the specification is obtained:

Checking wiring

• ‒ Remove battery.

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

Knock sensor 1 (G61)

• ‒ → Check wiring between test box and 3-pin connector for open circuit using current flow diagram.
          G61:
      Contact 1+socket    106
      Contact 2+socket     99
      Contact 3+socket    108
      Wire resistance: max. 1.5 ω
• ‒ Additionally check wires for short to one another.
      Specification: ∞ω

Knock sensor 2 (G66)

• ‒ → Check wiring between test box and 2-pin connector for open circuit using current flow diagram.
          G66:
      Contact 1+socket    107
      Contact 2+socket     99
      Wire resistance: max. 1.5 ω
• ‒ Additionally check wires for short to one another.
      Specification: ∞ω

If no wiring fault is detected:

• ‒ Loosen knock sensor and tighten again to 20 Nm.
• ‒ Perform a test drive again and check knock control specifications on display.

• During the road test the following operating conditions must be fulfilled:
• ‒ The coolant temperature must exceed 85 °C .

• ‒ When the temperature is reached, the operating conditions
      Idling
      Part throttle
      Full throttle
      Overrun
  must be attained several times.
• ‒ At full throttle the speed must exceed 3500 rpm.
• Again interrogate the control unit fault memory.

If the fault is still present:

• ‒ Replace the knock sensor/s (G61 or G66) , item 15.
• ‒ Interrogate fault memory, if necessary, repair any faults and then erase fault memory => Page 01-16, interrogating and erasing fault memory.
• ‒ Read-out the readiness code=> Page 01-64.