Knock sensors, checking: Notes

NOTE:

Knock Sensor (KS) 1 -G61- and Knock Sensor (KS) 2 -G66- cannot be checked electrically.
Use only gold-plated terminals for repair of knock sensor connector terminals.
To function correctly, it is important that the knock sensor tightening torque of 20 Nm (15 ft lb) be maintained.
When troubleshooting, check the knock sensor harness connector terminals for corrosion.

Connect VAG1551 or VAG1552 Scan Tool (ST) and press buttons -0- and -1- to insert "Engine Electronics" address word 01 (engine running at idle). See VAG1551 OR VAG1552 SCAN TOOL (ST), CONNECTING AND SELECTING "ENGINE ELECTRONICS" ADDRESS WORD 01 .

Indicated on display

Fig 1: VAG1551 Tool Display - Knock Control (1 Of 3)

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

Indicated on display

Fig 2: VAG1551 Tool Display - Knock Control (2 Of 3)

Press buttons -0-, -1 - and -5- to input display group number 15 (015), and press -Q- button to confirm input.

Indicated on display

Fig 3: VAG1551 Tool Display - Knock Control (3 Of 3)

Check specified values for knock control for bank 1 (display fields 1-4). See Fig 4.
- Engine speed for test: 3300 RPM
  
  Fig 4: Display Group 15: Knock Control, Bank 1, Testing At 3300 RPM
  
  If displayed values are not as specified in Fig 4, go to CHECKING KNOCK SENSORS .
Note on display groups 15 and 16:

At higher RPM, knock sensor signal voltage can reach up to approx. 35 volts.
Press -3- button to advance to display group 16.
Check specified values for knock control for bank 2 (display fields 1-4):
- Engine speed for test: 3300 RPM
  
  Fig 5: Display Group 16: Knock Control, Bank 2, Testing At 3300 RPM
  
  If displayed values are not as specified in Fig 5, go to CHECKING KNOCK SENSORS .
Note on display groups 15 and 16:

At higher RPM, knock sensor signal voltage can reach up to approx. 35 volts.
Press --> button to advance program sequence.
Press buttons -0- and -6- to select "End Output" (scan tool function 06), and press -Q button to confirm input.