Checking function

Connect VAG 1551 Scan Tool (VAG 1552). Start engine and select "Address word" 01 of engine control module. When doing this engine must be running at idling speed. See VAG 1551 SCAN TOOL (ST), CONNECTING AND SELECTING ENGINE CONTROL MODULE .

Indicated on display

Fig 1: Scan Tool Display - Checking Knock Sensor Function (Rapid Data Transfer)

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Press keys 0 and 8 for function "Read Measuring Value Block" and confirm entry with Q key.

Indicated on display

Fig 2: Scan Tool Display - Checking Knock Sensor Function (Read Measuring Value Block)

Courtesy of VOLKSWAGEN OF AMERICA, INC.

Press keys 0, 2 and 2 for "Display group number 22" and confirm entry with Q key.

Indicated on display: (1 to 4 Display zones)

Fig 3: Scan Tool Display - Checking Knock Sensor Function (Read Measuring Value Block 22)

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NOTE: Checking the knock sensor must be performed during a test drive because the diagnosis of the knock sensor is first activated above an engine speed of 3000 RPM and an engine load greater than 3 ms.

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

Perform a test drive and check knock control specifications on display (display zones 3 and 4)
Specification (cylinders 1 and 2): 0 to 15° CA
Change to display group 23 as follows:
Press key 3 (VAG 1551) or key -->(VAG 1552).

Indicated on display: (1 to 4 Display zones)

Fig 4: Scan Tool Display - Checking Knock Sensor Function (Read Measuring Value Block 23)

Courtesy of VOLKSWAGEN OF AMERICA, INC.

Check knock control specifications on display (display zones 3 and 4)

Specification (cylinders 3 and 4): 0 to 15 ° CA

If the specifications are obtained:

Press --> key.
Press keys 0 and 6 for "End Output" function and confirm input with Q key.
Switch ignition off.

If the specifications are not attained: