Knock sensors, checking
Notes:
- 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 and equipment
- Test box VAG 1598/31
- Hand multimeter VAG 1526 or multimeter VAG 1715
- Adapter set VAG 1594
- Wiring diagram
Test conditions
- On Board Diagnostic (OBD) must have recognized a malfunction on one or both knock sensors.
Checking resistances and wiring
- Separate 3-pin connector to Knock sensor (KS) 1 -G61- -1-.
- Measure resistance between contacts 1 + 2, 1 + 3 and 2 + 3 at connections to knock sensors.
Specification ∞ Ω
- Separate 3-pin connector to Knock sensor (KS) 2 -G66- -1-.
- Measure resistance between the contacts 1 + 2, 1 + 3 and 2 + 3 at connections to knock sensors.
Specification ∞ Ω
If the specification is not obtained:
- Replace knock sensor(s)
If the specification is obtained:
- Connect test box VAG 1598/31 to control module wiring harness. Engine control module remains disconnected.
- Check wiring between test box and 3-pin connector for open circuit using wiring diagram.
| -G61-: | -G66-: | |
| Contact 1 + socket | 106 | 107 |
| Contact 2 + socket | 99 | 99 |
| Contact 3 + socket | 108 | 108 |
| Wire resistance: Max. 1.5 Ω | ||
- Additionally check wires for short to one another.
If no wiring fault is detected:
- Loosen knock sensor and tighten again to 20 Nm.
- Test drive vehicle.
During the road test the following operating conditions must be fulfilled:
- Coolant temperature must exceed 80 ° C.
- When the temperature is reached, the operating conditions
Idling
Part throttle
Wide Open throttle
Overrun
must be attained several times.
- At Wide Open throttle the speed must exceed 3500 RPM.
- Again check control module DTC memory.
If the malfunction is still present:
- Replace knock sensor(s).