With Manufacturer's Scan Tool
Knock Sensors, Checking
NOTE:
- It is extremely important to keep to the tightening torque of 20 Nm to ensure the knock sensors perform perfectly.
- Only gold-plated contacts may be used when servicing the knock sensor connector contacts.
Special tools, test equipment and auxiliary items
- Scan tool V.A.G 1551 or vehicle system tester V.A.G 1552 with cable V.A.G 1551/3B
- Test box V.A.G 1598/31
- Hand multimeter V.A.G 1526 or multimeter VAG 1715
- Adapter set V.A.G 1594
- Wiring diagram
Check conditions
- On Board Diagnostic (OBD) must have recognized a malfunction in one or both knock sensors, checking and erasing DTC memory. Refer to "Displaying, Reading and Erasing Trouble Codes/With Manufacturers Scan Tool/DTC Memory, Checking And Erasing", Testing and Inspection
- Coolant temperature must be at least 85 °C, see display group 28, display zone 3
Checking function
- Connect scan tool V.A.G 1551 (V.A.G 1552). Start engine and select "Address word" 01 of engine control module. When doing this the 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/VAG 1551 Scan Tool", Testing and Inspection
Indicated on display
Rapid data transfer HELP
Select function XX
- Press keys 0 and 8 for the 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 the "Display group number 28" and confirm entry with Q key.
Indicated on display (1-4 = 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 knock sensors OBD is not activated until the engine speed exceeds 2000 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 carrying out a test drive.
Display Group 28:
If the specification is attained:
- Press -> key.
- Press keys 0 and 6 for the function "End output" and confirm entry with the Q key.
- Switch off ignition.
Continuation:
If the specifications are not obtained:
- Press -> key.
- Press keys 0 and 6 for the function "End Output" and confirm entry with the Q key.
- Switch off ignition.
- Separate the 2-pin connector to knock sensor 1 (G61) -1- and/or 2-pin connector to knock sensor 2 (G66) -2-.
- Measure resistance between the contacts 1 + 2 at the connections to knock sensors.
Specification: Infinity Ohms
If the specification is not obtained:
- Replace the knock sensor/s (G61 or G66), item 12 or item 17.
- Check DTC memory, if necessary, repair any malfunctions and then erase DTC memory, checking and erasing DTC memory. Refer to "Displaying, Reading and Erasing Trouble Codes/With Manufacturers Scan Tool/DTC Memory, Checking And Erasing", Testing and Inspection
- Read-out the readiness code. If the DTC memory has been erased or the engine control module was disconnected from permanent positive, the readiness code must be generated again.
Refer to "Monitors Trips and/or Drive Cycle/Displaying Readiness Code", Testing and Inspection
Refer to "Monitors Trips and/or Drive Cycle/Generating Readiness Code", Testing and Inspection
If the specification is obtained:
- Check wiring.
Checking wiring
- 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:
Contact 1 + socket 106 107
Contact 2 + socket 99 99
Wire resistance: Max. 1.5 Ohms
- Additionally check wires at socket 99 for short to sockets 106 and 107.
Specification: Infinity Ohms
If no malfunctions in wiring are detected:
- Loosen knock sensor and tighten again to 20 Nm.
- Perform a test drive again and check knock control specifications on display.
During the road test coolant temperature must exceed 85 °C
When the temperature is reached, the operating conditions must be attained several times:
- Idle
- Part throttle
- Full throttle
- Over run
- At full throttle the speed must exceed 3500 RPM.
- Again check the control module DTC memory.
If the malfunction is still present:
- Replace the knock sensor/s (G61 or G66), item 12 or item 17.
- Check DTC memory, if necessary, repair any malfunctions and then erase DTC memory, checking and erasing DTC memory. Refer to "Displaying, Reading and Erasing Trouble Codes/With Manufacturers Scan Tool/DTC Memory, Checking And Erasing", Testing and Inspection
- Read-out the readiness code. If the DTC memory has been erased or the engine control module was disconnected from permanent positive, the readiness code must be generated again.
Refer to "Monitors Trips and/or Drive Cycle/Displaying Readiness Code", Testing and Inspection
Refer to "Monitors Trips and/or Drive Cycle/Generating Readiness Code", Testing and Inspection