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Knock Sensor and Knock Sensor Control, Checking




Knock sensor and knock sensor control, checking

Required special tools and test equipment
- VAG 1551/1552 Scan Tool (ST) with VAG 1551/3 adapter cable
- VAG 1598/22 test box
- Multimeter US 1119 (Fluke 83 or equivalent)
- VW 1594 connector test kit
- Wiring diagrams

Checking
- Connect VAG 1551/1552 Scan Tool (ST) and press buttons -0- and -1- to insert "Engine Electronics" address word 01 (with engine running at idle).[1][2]Scan Tool Connecting and Initial Checks
Indicated on display


Rapid data transfer HELP
Select function XX


- Press buttons -0- and -8- to select "Read Measuring Value Block" function 08, and press -Q- button to confirm input.

Indicated on display


Read Measuring Value block HELP
Input display group number XXX


- Press buttons corresponding to following display group numbers and press -Q- button to confirm input.
- 022: Display group 22, for cylinders 1 and 2
- 023: Display group 23, for cylinders 3 and 4
- 024: Display group 24, for cylinders 5 and 6

Indicated on display (1-4 = display groups)


Read Measuring Value Block 22 ->
1 2 3 4


NOTE: The test must be carried out during a road test because the knock sensor system is only active with engine speed greater than 2600 RPM and engine load greater than 3 ms.


- Road test and compare display with specified values for knock sensor system in display field 1-4.


WARNING!
A second technician is required to operate the VAG 1551 scan tool during the road test.
Safety precautions


Display Group 22:






If displayed values are OK:
- Press -> button.
- Press buttons -0- and -6- to select "End Output" function 06, and press -Q- button to confirm input.
- Check readiness code.If Diagnostic Trouble Code (DTC) memory has been erased, or ECM has been disconnected, generate new readiness code.
Readiness Code Reading
Readiness Code, Generating

Evaluation of display groups 22, 23 and 24


Display Groups 22,23, And 24:






Continuation
- Disconnect 3-pin connector from Knock Sensor (KS) 1 -G61-.







- Connect multimeter US 1119 (Fluke 83 or equivalent) to measure resistance between connector terminals, using adapters from VW 1594 connector test kit.
- Knock sensor terminals 1 and 2
- knock sensor terminals 1 and 3
- Knock sensor terminals 2 and 3
- Specified value: Infinity Ohms
If resistance is OK (no continuity):
- Connect VAG 1598/22 test box to Motronic ECM harness connector.Connecting VAG 1598/22 Test Box







- Check wiring for open circuit between ECM/test box and 3-pin harness connector, according to wiring diagram.
- Connector terminal 1 to ECM/test box socket 68
- Connector terminal 2 to ECM/test box socket 67
- Connector terminal 3 to ECM/test box socket 67
- Specified value: max. 1.5 Ohms







- Check wiring for short circuits between terminals of 3-pin connector, and between connector and ECM/test box.
- Connector terminal 2 to ECM/test box socket 68
- Connector terminal 3 to ECM/test box socket 68
- Specified value: Infinity Ohms

If the wiring is OK:
- Loosen knock sensor and tighten to 20 Nm (15 ft lb).
If the malfunction still exists (stored in DTC memory):
- Replace Knock Sensor (KS) 1 -G61-.
- Check readiness code.Readiness Code Reading







If Diagnostic Trouble Code (DIC) memory has been erased, or ECM has been disconnected, generate new readiness code.Readiness Code, Generating
- Disconnect 3-pin connector from Knock Sensor (KS) 2 -G66-.
- Connect multimeter US 1119 (Fluke 83 or equivalent) to measure resistance between connector terminals, using adapters from VW 1594 connector test kit.
- Knock sensor terminals 1 and 2
- Knock sensor terminals 1 and 3
- Knock sensor terminals 2 and 3
- Specified value: Infinity Ohms
If resistance is OK (no continuity):
- Connect VAG 1598/22 test box to Motronic ECM harness connector.







- Check wiring for open circuit between ECM/test box and 3-pin harness connector, according to wiring diagram.
- Connector terminal 1 to ECM/test box socket 60
- Connector terminal 2 to ECM/test box socket 67
- Connector terminal 3 to ECM/test box socket 67
- Specified value: max. 1.5 Ohms
- Check wiring for short circuits between terminals of 3-pin connector, and between connector and ECM/test box.
- Connector terminal 2 to ECM/test box socket 60
- Connector terminal 3 to ECM/test box socket 60
- Specified value: Infinity Ohms

If the wiring is OK:
- Loosen knock sensor and tighten to 20 Nm (15 ft lb).

If the malfunction still exists (stored in DTC memory):
- Replace Knock Sensor (KS) 2 -G66-.
- Check readiness code.If Diagnostic Trouble Code (DTC) memory has been erased, or ECM has been disconnected, generate new readiness code.
Readiness Code Reading
Readiness Code, Generating
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