With Manufacturer's Scan Tool

Knock Sensors, Checking

NOTE:
- To remove and install knock Sensors, intake manifold must be removed.
- For the Knock Sensors to function properly, it is important for tightening torque to be exactly 20 Nm.
- When servicing terminals in harness connector of Knock Sensors, use only gold-plated terminals.

Special tools and equipment
- VAG 1598/31 test box
- VAG 1526 multimeter or VAG 1715 multimeter
- VAG 1594 connector test kit
- Wiring diagram

Test condition
- The On Board Diagnostic (OBD) must have identified a DTC on one or both Knock Sensors.

Functional Test

Functional test of knock control and Knock Sensors; read measuring value block, display groups 22 - 28. Refer to Scan Tool Testing/Measuring Value Blocks (Function 08)/Reading Reading Measuring Value Blocks

Testing Resistances and Wires






- Disconnect 3-pin harness connector going to Knock Sensor (KS) 1 (-G61-, bank 1) (1) and/or 3-pin harness connector going to Knock Sensor (KS) 2 (-G66-, bank 2) (2).
- Measure resistance between terminals 1 + 2, 1 + 3, and 2 + 3 at connectors to Knock Sensors.
Expected value: infinity Ohms






- Connect VAG 1598/31 test box to control module wiring harness. Engine Control Module (ECM) is not connected.






- Check for breaks in wires between test box and 3-way connector (see wiring diagram).
-G61-: -G66-:
Terminal 2 + socket 106 107
Terminal 2 + socket 99 99
Terminal 3 socket 108 108
Wire resistance: max. 1.5 Ohms

- Also test lines at socket 108 for shorts to sockets 106 and 107.
Expected value: infinity Ohms

If no malfunctions are found in wires:
- Loosen Knock Sensor (KS) and then retighten it to 20 Nm.
- Perform a road test.

The following operating conditions must be obtained during road test:
- Coolant temperature must rise to above 80 °C.
- Once the temperature is reached, the following conditions
Idle
Partial throttle
Wide Open Throttle (WOT)
Deceleration mode
must be reached several times each.

- Engine speed must be increased to above 3500 RPM during Wide Open Throttle (WOT).

- Check control module DTC memory again.

If it continues to complain:
- Replace knock Sensor(s) item 11 or 10.