Knock Sensors, Checking

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
- mounting bolts of knock sensors tightened to 20 Nm.
- Ignition switched off.

Test sequence

Cylinder bank 1







- Disconnect the 3-pin harness connector to Knock Sensor (KS) 1 - G61 - (arrow).

Cylinder bank 2







- Disconnect the 3-pin harness connector to Knock Sensor (KS) 2 - G66 - (arrow).

Cylinder bank 1 and 2

NOTE:
- Cylinder bank 1 = in direction of travel, 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:

Cylinder bank 1
- Knock Sensor (KS) 1 - G61 -.
Cylinder bank 2
- Knock Sensor (KS) 2 - G66 -.

- Erase DTC memory of Engine Control Module (ECM). Diagnostic Mode 04 - Erase DTC Memory
- Generate readiness code. Monitors, Trips, Drive Cycles and Readiness Codes

If specified value is obtained:
- Check wires according to wiring diagram.

Checking wiring
- Connect test box to control module wiring harness. Connecting Test Box 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 2







Cylinder bank 1 and 2
- Also check wires for short circuit to each other.
Terminal 1 + socket 108

Specified value: infinity ohms.

- Erase DTC memory of Engine Control Module (ECM). Diagnostic Mode 04 - Erase DTC Memory
- Generate readiness code. Monitors, Trips, Drive Cycles and Readiness Codes

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