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
Requirements
- Knock sensor securing bolt tightened to 20 Nm.
- Ignition switched off.
Work 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 connections to respective knock sensors.
Specified value: ∞ Ω
If specified value is not obtained:
- Replace respective knock sensor:
- Knock Sensor (KS) 1 -G61- or Knock Sensor (KS) 2 -G66-. Refer to Knock sensors 1 and 2 cylinder bank 1
- Knock sensor 3 -G198-. Refer to Knock sensor 3 cylinder bank 2
- Knock sensor 4 -G199-. Refer to Knock sensor 4 cylinder bank 2
- Erase DTC memory of Engine Control Module (ECM). Refer to Diagnostic mode 4: Reset/erase diagnostic data
- Generate readiness code. Refer to Readiness code, generating
If specified value is obtained:
- Check wiring.
Checking wiring
- Connect test box to control module wiring harness. Refer to 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 Ω
Cylinder bank 1
| Component | Connector | Test box |
| Knock Sensor (KS) 1 -G61- | Terminal 1 | Socket 106 |
| Terminal 2 | Socket 99 | |
| Terminal 3 | Socket 99 | |
| Knock Sensor (KS) 2 -G66- | Terminal 1 | Socket 107 |
| Terminal 2 | Socket 99 | |
| Terminal 3 | Socket 99 |
Cylinder bank 2
| Component | Connector | Test box |
| Knock sensor 3 -G198- | Terminal 1 | Socket 31 |
| Terminal 2 | Socket 99 | |
| Terminal 3 | Socket 99 | |
| Knock sensor 4 -G199- | Terminal 1 | Socket 16 |
| Terminal 2 | Socket 99 | |
| Terminal 3 | Socket 99 |
Cylinder bank 1 and 2
- Also check wires for short circuit to each other.
Terminal 1 + socket 99
Specified value: ∞ Ω
- Erase DTC memory of Engine Control Module (ECM). Refer to Diagnostic mode 4: Reset/erase diagnostic data
- Generate readiness code. Refer to Readiness code, generating
If no malfunctions are found in wires:
- Replace Engine Control Module (ECM). Refer to Engine Control Module (ECM), replacing .