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With Manufacturer 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 1 -G61- and 2 -G66- have a direct 2-pole connector and therefore no terminal for the shielding in the socket.
- Only gold-plated terminals may be used when servicing the knock sensor connector terminals.
- The terminal surfaces between knock sensor and cylinder block must be free of corrosion, dirt and grease.


Special tools and equipment
- Test box V.A.G 1598/31
- Hand multimeter V.A.G 1526 or multimeter V.A.G 1715
- Adapter set V.A.G 1594
- Wiring diagram

Checking conditions
- On Board Diagnostic (OBD) must have recognized a malfunction in one or both knock sensors. Refer to "Displaying and Reading Trouble Codes/With Manufacturers Scan Tool/DTC Memory Checking and Erasing" Testing and Inspection
- The engine speed must be at least 2650 RPM, See Display group 28, Display field 1
- The engine load musts be at least 40.0 %
See display group 28, display zone 2
- Coolant temperature must be at least 80 °C, See display group 28, display zone 2.

Checking sequence
- Connect scan tool V.A.G 1551 (V.A.G 1552). Start engine and select "Address word" 01 of engine control module. Engine must be running at idle speed. Connecting scan tool and selecting engine control module. Refer to "Scan Tool Testing/Scan Tool Connecting and Initial Checks/VAG1551 Scan Tool" Testing and Inspection

Indicated on display


Rapid data transfer HELP
Select function XX


- Press buttons -0- and -8- for function "Read Measuring Value Block" and confirm entry with Q button.

Indicated on display


Read Measuring Value Block
Input display group number XXX


- Press buttons -0-, -2- and -8- for the "Display group number 28" and confirm entry with Q button.

Indicated on display (1 to 4 = Display zones)


Read Measuring Value Block 28 ->
1 2 3 4


NOTE: Checking the knock sensors must be performed during a test drive because the knock sensors OBD is not activated until the engine speed exceeds 2650 RPM and the engine is loaded by more than 40 %.


- Perform a test drive and let a 2nd person check knock control specifications on display (display zone 4).

Observe the valid safety precautions when carrying out a test drive.

- Check specification for knock control in display zone 4.
Specification: Syst. OK

If the specification is obtained:
- Press -> button.
- Press buttons 0 and 6 for the "End output" function and confirm input with the Q button.
- Switch ignition off.

If the specification is not obtained:

Checking resistances and wiring







- Separate 2-pin connector to knock sensor 1 -G61- -1- and/or 2-pin connector to knock sensor 2 -G66- -2-.







- Measure resistance between terminals 1+2 at connections to knock sensors.
Specification Infinity Ohms

If the specification is not obtained:
- Replace knock sensor(s)
- Check DTC memory, if necessary, repair any malfunctions and then erase DTC memory. Refer to "Displaying and Reading Trouble Codes/With Manufacturers Scan Tool/DTC Memory Checking and Erasing" Testing and Inspection
- Read readiness code. If DTC memory has been erased or engine control module was disconnected from battery (B+) positive, readiness code must be generated again.
Refer to "Monitors, Trips and/or Drive Cycle/Readiness Code, Displaying" Testing and Inspection
Refer to "Monitors, Trips and/or Drive Cycle/Readiness Code, Generating" Testing and Inspection

If the specification is obtained:
- Remove inner plenum chamber cover, left:







- Connect test box V.A.G 1598/31 to control module wiring harness. The engine control module is not connected by this action.







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

G61: G66:
Terminal 1 + socket 106 107
Terminal 2 + socket 99 99

Wire resistance: Max. 1.5 Ohms

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

If no malfunctions in wiring are detected:
- Loosen knock sensor and tighten again to 20 Nm.
- Perform a test drive again.

During the road test the following operating conditions must be fulfilled:
- The coolant temperature must exceed 80 °C
- When the temperature is reached, the operating conditions must be attained several times:
Idling
Part throttle
Enrichment
Full throttle
Over run
- At full throttle 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. Refer to "Displaying and Reading Trouble Codes/With Manufacturers Scan Tool/DTC Memory Checking and Erasing" Testing and Inspection
- Read readiness code. If DTC memory has been erased or engine control module was disconnected from permanent positive, readiness code must be generated again.
Refer to "Monitors, Trips and/or Drive Cycle/Readiness Code, Displaying" Testing and Inspection
Refer to "Monitors, Trips and/or Drive Cycle/Readiness Code, Generating" Testing and Inspection
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