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Motronic Injection and Ignition System > < Checking components

Leon Mk1

Knock sensor: checking
Knock sensor: checking
Special tools and workshop equipment required
   
t  Hand multimeter -V.A.G 1526 A- or multimeter -V.A.G 1715-
t  Auxiliary measuring set -V.A.G 1594 C-
t  Test box -V.A.G 1598/18-
t  Current flow diagram
Test conditions
l  Knock sensor fault recognised by self-diagnosis
Checking process
  W00-0431
–  Connect test box -V.A.G 1598/18- to control unit wiring harness.
–  Check wiring and the knock sensor for short circuits.
  N24-0334
Test box -V.A.G 1598/18-, socket
19 + 39, 39 + 45, 19 + 45
Specification: ∞ Ω

If no short circuits are detected:
–  Removing the starter motor: → Rep. Gr.27.
   
–  Remove connector -1- from knock sensor 1 -G61--2-.
–  Check wiring for open circuit between the test box and the knock sensor using current flow diagram.
  N28-0015
ContactTest box -V.A.G 1598/18-, socket
139
219
Wire resistance: 1,5 Ω max.

–  Measure resistance between contacts in the knock sensor.
   Specification: ∞ Ω
If no wiring fault is detected:
–  Loosen knock sensor and tighten again to 20 Nm.
–  Carry out test drive.
t  The coolant temperature must exceed 80 °C.
t  Once the temperature is reached, the operating conditions must be reached several times: idling; part throttle; full throttle; overrun
t  At full throttle, revolutions must exceed 3,500 rpm.
–  Interrogate the control unit fault memory again.
If the fault is still present:
–  Replace knock sensor -G61- → Item.
   

Motronic Injection and Ignition System > < Checking components