Jetta GLS Wagon L4-2.0L (AZG) (2002)
Knock Sensor: Testing and Inspection
With Manufacturer's Scan Tool
Knock Sensor, Checking
NOTE:
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It is extremely important to keep to the tightening torque of 20 Nm to make sure the knock sensors perform perfectly.
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Knock sensor (KS) 1 -G61- and Knock sensor (KS) 2 -G66- have a direct 2-pin connection and therefore have no shielding in the connector.
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Only gold-plated contacts may be used when servicing the knock sensor connector contacts.
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Contact surfaces between knock sensor and cylinder block must be free of corrosion and dirt
Special tools and equipment
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Test box VAG1598/31
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Multimeter Fluke 83 or equivalent
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Adapter set VAG1594
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Wiring diagram
Check conditions
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On Board Diagnostic must have recognized a malfunction on one or both knock sensors.
See: Computers and Control Systems/Testing and Inspection/Reading and Clearing Diagnostic Trouble Codes/Reading Diagnostic Trouble Codes
See: Computers and Control Systems/Testing and Inspection/Reading and Clearing Diagnostic Trouble Codes/Clearing Diagnostic Trouble Codes
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Engine speed must be at least 2650 RPM, see display group 28, display field 1
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Engine load musts be at least 40.0%, see display group 28, display zone 2
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Coolant temperature must be at least 80°C, see display group 28, display zone 2.
Test sequence
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Connect scan tool VAG 1551 ((VAG 1552). Start engine and select "Address word" 01 of engine control module. Engine must be running at
idling speed. See: Computers and Control Systems/Testing and Inspection/Reading and Clearing Diagnostic Trouble Codes/Scan Tool
Connecting
Indicated on display:
Rapid data transfer
HELP
Select function XX
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Press keys 0 and 8 for the function "Read measuring value block" and confirm entry with Q key.
Indicated on display:
Read measuring value block
Input display group number XXX
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Press keys 0, 2 and 8 for the "Display group number 28" and confirm entry with Q key.
Indicated on display: (1 to 4 Display zones)
Read measuring value block 28
->
1
2
3
4
NOTE: The knock sensor test must be performed during a road test since knock sensor diagnostic is only active at engine speeds above 2650 RPM with
an engine load of more than 40%.
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Test drive vehicle with a 2nd person to observe display.
Observe the valid safety precautions when performing a test drive.
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Check specification for knock control in display zone 4.
Specification: Syst. OK
If the specification is obtained:
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Press -> key.
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Press keys 0 and 6 for the "End output" function and confirm input with the Q key.
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Switch off ignition.