Knock Sensors, Checking
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.
Special tools and workshop equipment required
- Multimeter VAG1526 or multimeter VAG1715
- Connector test kit VAG1594
- 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
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: ∞ Ω
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 4: Reset/erase diagnostic data.
-- Generate readiness code.
If specified value is obtained:
-- Check wires according to wiring diagram.
Checking wiring
-- Connect test box to control module wiring harness, connect 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 Ω
Cylinder bank 1
| Component | Connector | Test box |
|---|---|---|
| Knock Sensor (KS) 1 -G61- | Terminal 1 | Socket 99 |
| Terminal 2 | Socket 106 | |
| Terminal 3 | Socket 108 |
Cylinder bank 2
| Component | Connector | Test box |
|---|---|---|
| Knock Sensor (KS) 2 -G66- | Terminal 1 | Socket 99 |
| Terminal 2 | Socket 107 | |
| Terminal 3 | Socket 108 |
Cylinder bank 1 and 2
-- Also check wires for short circuit to each other.
Terminal 1 + socket 108
Specified value: ∞ Ω
-- Erase DTC memory of Engine Control Module (ECM), Diagnostic mode 4: Reset/erase diagnostic data.
-- Generate readiness code.
If no malfunctions are found in wires:
-- Replace Engine Control Module (ECM) ENGINE CONTROL MODULE, REPLACING .