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 the harness connector.

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

Test requirements







- Fuses on E-box in engine compartment, left side, must be OK:

NOTE: Fuses on this fuse holder are labelled "SB" in the wiring diagram.







- Fuses on fuse holder in instrument panel, left side, must be OK:

NOTE: Fuses on this fuse holder are labelled "SC" in the wiring diagram.

- Ground (GND) connections between engine and chassis must be OK.
- mounting bolts of knock sensors tightened to 20 Nm.
- Ignition switched off.

Test sequence

Observe safety precautions.
Observe rules for cleanliness.

- Remove engine cover, removing and disassembling air filter/engine cover.







- Disconnect corresponding 3-pin harness connector to knock sensor:
2 - Green harness connector for Knock Sensor (KS) 1 -G61-
3 - Brown harness connector for Knock Sensor (KS) 2 -G66-
(not visible, above harness connector for Knock Sensor 1)

Checking resistance







- Check resistance between terminals 1 and 2 at connector to sensor. Specified value: 4.5 to 5.0 M Ohms
- Check sensor for short circuit between terminals 1 and 3 as well as 2 and 3.

Specified value: Infinity Ohms

If specified values are not obtained:
- Replace respective knock sensor:
- Knock Sensor (KS) 1 -G61-, item 1,
- Knock Sensor (KS) 2 -G66-, item 2.

- 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 values are obtained:
- Check wires to Engine Control Module (ECM) according to wiring diagram.

Checking wires to Engine Control Module (ECM)
- Connect test box to 60-pin connector of wiring harness. Test Box, Connecting For Wiring Test

Engine Control Module (ECM) is not connected.







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

Wire resistance: max. 3.0 Ohms







- Check wires for short circuit to each other.

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) -J623-.