With Manufacturer's Scan Tool

Knock Sensor, Checking

NOTE:
- It is extremely important to keep to the tightening torque of 20 Nm to ensure the knock sensors perform perfectly.
- Knock sensors (KS) 1 -G61- and knock sensors (KS) 2 -G66- have a direct 2-pin connector and consequently no contact for the shielding in the connector.
- Only gold-plated contacts may be used when servicing the knock sensor connector contacts.
- Contact surfaces between knock sensor and cylinder block must be free of corrosion, dirt and grease.

Special tools and equipment
- V.A.G 1598/31 test box
- V.A.G 1526 A or Fluke 83 multimeter
- V.A.G 1594 C adapter set
- Wiring diagram

Test conditions
- On Board Diagnostic (OBD) must have recognized a malfunction on one or both knock sensors. DTC Memory, Checking and Erasing (Functions 02 and 05)
- Coolant temperature must be at least 85 degrees C, see display group 28, display zone 3.

Checking function
- Connect V.A.G 1551 scan tool (V.A.G 1552). Start engine and select "Address word" 01 of engine control module. Engine must be running at idling speed.(Connecting scan tool and selecting engine control module. [1][2][3]Connecting VAG 1551 Scan Tool)

Indicated on display:

Rapid data transfer HELP
Select function XX

- Press keys 0 and 8 for function "Read measured value block" and confirm entry with Q key.

Indicated on display:

Read measured value block
Input display group number XXX

- Press keys 0, 2 and 8 for "Display group number 28" and confirm entry with Q key.

Indicated on display: (1 to 4 = Display zones)

Read measured value block 28
1 2 3 4

NOTE: Checking the knock sensors must be performed during a test drive because the diagnosis of the knock sensors is not activated until the engine speed exceeds 1800 rpm and the engine is loaded by more than 40%.

- Perform a test drive and check knock control specifications on display (display zone 4).

Observe the valid safety precautions when performing a test drive.







If the specification is attained:
- Press -> key.
- Press keys 0 and 6 for function "End output" and confirm entry with Q key.
- Switch ignition off.

Continuation:

If the specifications are not obtained:
- Press -> key.
- Press keys 0 and 6 for function "End output" and confirm entry with Q key.
- Switch ignition off.

Checking resistance of knock sensors

Knock sensor 1 -G61-







- Disconnect 2-pin harness connector to Knock Sensor (KS) 1 -G61- (-1-) and/or 2-pin harness connector to Knock Sensor (KS) 2 -G66- (-2-).







- Measure resistance between contacts 1+2 at connections to knock sensors.
Specification: Infinite Ohms

If the specification is not obtained:
- Replace knock sensor(s).
- Check DTC Memory, if necessary, repair any malfunctions and then Erase DTC Memory. DTC Memory, Checking and Erasing (Functions 02 and 05)
- Read readiness code. If DTC memory has been erased or engine control module was disconnected from permanent positive, readiness code must be generated again.
Monitors, Trips, Drive Cycles and Readiness Codes
Monitors, Trips, Drive Cycles and Readiness Codes

If the specification is obtained:
Check wiring.

Checking wiring







- Connect V.A.G 1598/31 test box to control module wiring harness. Engine control module remains disconnected.







- Check wiring between test box and 2-pin connector for open circuit according to wiring diagram.







- Additionally check wires for short to one another.
Specification: Infinite Ohms

If no wiring malfunciton is detected:
- Loosen knock sensor and tighten again to 20 Nm.
- Perform a test drive again and check knock control specifications on display.

Observe the valid safety precautions when road testing vehicle.
During the road test the following operating conditions must be fulfilled:

- Coolant temperature must exceed 85 degrees C.
- When the temperature is reached, the operating conditions
Idling
Part throttle
Wide open throttle
Overrun
must be attained several times.

- At wide open throttle the engine speed must exceed 3500 rpm.
- Again check control module DTC memory.

If the malfunction is still present:
- Replace knock sensor(s).
- Check DTC Memory, if necessary, repair any malfunctions and then Erase DTC Memory. DTC Memory, Checking and Erasing (Functions 02 and 05)
- Read readiness code. If DTC memory has been erased or engine control module was disconnected from permanent positive, readiness code must be generated again.
Monitors, Trips, Drive Cycles and Readiness Codes
Monitors, Trips, Drive Cycles and Readiness Codes