Knock Sensor: Testing and Inspection

Knock sensors, checking


NOTE:
- Contact surfaces between knock sensor and cylinder block must be free of corrosion, dirt and grease.
- For the knock sensors to function properly, it is important for tightening torque to be exactly 20 Nm.
- Use only gold-plated terminals when servicing terminals in harness connector of knock sensors.


Recommended special tools and equipment
- VAG1526 multimeter or VAG1715 multimeter
- VAG1594 connector test kit
- Wiring diagram

Test requirements
- Knock sensor securing bolt tightened to 20 Nm.
- Ignition switched off.

Test sequence

Cylinder bank 1







- Disconnect 3-pin harness connector to knock sensors:
1 Knock Sensor (KS) 2 -G66-, brown
2 Knock Sensor (KS) 1 -G61-, black

Cylinder bank 2







- Disconnect 3-pin harness connector to knock sensors:
1 Knock sensor 4 -G199-, gray
2 Knock sensor 3 -G198-, brown

Cylinder bank 1 and 2


NOTE:
- Cylinder bank 1 = in driving direction, right
- Cylinder bank 2 = in driving direction, left
- Before disconnecting harness connectors, mark allocation to component.


Checking resistances







- Measure resistance between terminals 1 + 2, 1 + 3 and 2 + 3 at the connections to the respective knock sensors.
Specified value: Infinity Ohms

If specified value is not obtained:
- Replace the respective knock sensor:
- Knock Sensor (KS) 1 -G61- or Knock Sensor (KS) 2 -G66-, Fig. 2
- Knock sensor 3 -G198-, Fig. 3
- Knock sensor 4 -G199-, Fig. 4

- Erase DTC memory of Engine Control Module (ECM), Diagnostic mode 4: Reset/erase diagnostic data.
- Generate readiness code. Monitors, Trips, Drive Cycles and Readiness Codes

If specified value is obtained:

Checking wiring
- Connect test box to control module wiring harness, connect test box for wiring test. Test Box, Connecting For Wiring Test







- Check wires between test box and 3-pin connector to Engine Control Module (ECM) for open circuit according to wiring diagram.
Wire resistance: max. 1.5 Ohms

Cylinder bank 1

Cylinder Bank 1:

Cylinder bank 2

Cylinder Bank 2:

Cylinder bank 1 and 2
- Also check wires for short circuit to each other.
Terminal 1 + socket 99
Specified value: Infinity Ohms

- Erase DTC memory of Engine Control Module (ECM), Diagnostic mode 4: Reset/erase diagnostic data.
- Generate readiness code. Monitors, Trips, Drive Cycles and Readiness Codes

If no malfunctions are found in wires:
- Replace Engine Control Module (ECM).