With Manufacturer's Scan Tool
Knock Sensor, Checking
NOTE:
- The terminal surfaces between Knock sensor (KS) and cylinder block must be free of corrosion, dirt and grease.
- Knock sensor (KS) 2 -G66- has a direct 2-pin connector and therefore no terminal for the shielding in the connector.
- It is extremely important to keep to the torque setting of 20 Nm to ensure the Knock sensors (KS) perform perfectly.
- Only gold-plated terminals may be used when servicing the Knock sensor (KS) connector terminals.
Special tools, workshop equipment, testers, measuring instruments and auxiliary items required
- VAG 1551 Scan tool (or VAG 1552 Scan tool) with VAG 1551/3 adapter cable
NOTE: All functions which could previously be performed with VAG 1551/1552 can also be performed with the VAS 5051.
- VAG 1526 Hand multimeter or VAG 1715 multimeter
- VAG 1594 adapter set
- VAG 1598/31 test box
- Electrical Wiring Diagrams
Test prerequisites
- The fuses must be OK.
- The battery voltage must be at least 11.5 V.
- All electrical accessories, e.g. lights and rear window heating must be switched off.
- If the vehicle is equipped with air conditioning, it must be turned off.
- Selector lever must be in position "P" or "N" on vehicles with an automatic transmission.
- Knock sensor (KS) malfunction detected by On Board Diagnostic (OBD). Refer to "Computers and Control Systems/Testing and Inspection".
Testing and Inspection
- The signal from brake light switch and brake pedal switch must be OK, Checking.
Testing and Inspection
- Engine Coolant Temperature (ECT) must be at least 85 degrees C, See display group 28, display zone 3.
Functional check
- Connect VAG 1551 Scan tool ((VAG 1552) and select engine electronics control module with the "Address word" 01. When doing this the engine must be running at idling speed: (Connecting scan tool and selecting engine electronics control module). Refer to "Scan Tool Testing/Scan Tool Connecting and Initial Checks",
Testing and Inspection
Indicated on display:
Rapid data transfer HELP
Select function XX
- Press buttons -0- and -4- for function "Initiate basic setting" and confirm entry with -Q- button.
Indicated on display:
Basic setting
Input display group number XXX
- Press buttons -0-, -2- and -8- for the "Display group number 28" and confirm entry with -Q- button.
Indicated on display: (1 to 4 = display zones)
System in basic setting 28 ->
1 2 3 4
Only continue with the test when
- The Engine Coolant Temperature (ECT) is above 85 degrees C - Display zone 3-
- Depress brake pedal and hold.
- Depress accelerator down to full throttle position.
Engine speed will be increased by Engine Control Module (ECM) to approx. 2300 rpm.
- Depress brake pedal and accelerator down and hold until display in display zone 4 jumps from "Test OFF" to "Test ON".
- Depress and hold brake pedal and accelerator until display zone 4 displays specification "Syst. OK."
- Release brake and accelerator pedals.
- Press the -> button.
- Press buttons -0- and -6- for function "End output" and confirm entry with the -Q- button.
- Switch off ignition.
If "Syst.n.OK." appears in display zone 4:
- Check the resistance and wiring for Knock sensors (KS).
Checking resistance and wiring
Knock sensor (KS) 1 -G61-
- Separate 3-pin connector to Knock sensor (KS) 1 -arrow- on right of cylinder head.
- Measure resistance between terminals 1 and 2, 1 and 3, and 2 and 3 at connector to Knock sensor (KS) 1 -G61-.
Specification: infinity ohms
Knock sensor (KS) 2 -G66-
- Pull 2-pin connector off Knock sensor (KS) 2 -arrow- (on inlet side of cylinder head).
- Now measure resistance between terminals 1 and 2 at connector to Knock sensor (KS) 2 -G66-.
Specification: infinity ohms
If the specifications are not obtained:
- Replace Knock sensors (KS) -G61- or -G66-, item 7 or item 17.
- Check DTC memory, repair malfunctions if necessary and then erase DTC memory. Refer to "Displaying and Reading Trouble Codes/With Manufacturer Scan Tool/DTC Memory Checking and Erasing".
Testing and Inspection
- Read readiness code. If the DTC memory has been erased or the Engine Control Module (ECM) was disconnected from battery positive, the readiness code must be generated again. Refer to "Monitors, Trips and/or Drive Cycle (Readiness Codes)/Reading Readiness Code".
Testing and Inspection.
Refer to "Monitors, Trips and/or Drive Cycle (Readiness Codes)/Generating Readiness Code".
Testing and Inspection
If the specifications are obtained:
- Remove wiper arms and cowl panel:
- Connect VAG 1598/31 test box to control module wiring harness. The Engine Control Module (ECM) remains disconnected.
Knock sensor (KS) 1 -G61-
- Check wiring for open circuit between test box and 3-pin connector referring to Electrical Wiring Diagrams
terminal 1 and socket 106
terminal 2 and socket 99
terminal 3 and socket 108
Wire resistance: max. 1.5 ohms
- Additionally check wires for short to one another.
Specification: infinity ohms
Knock sensor (KS) 2 -G66-
- Now check wiring for open circuit between test box and 2-pin connector referring to Electrical Wiring Diagrams.
terminal 1 and socket 107
terminal 2 and socket 99
Wire resistance: max. 1.5 ohms
- Additionally check wires for short to one another.
Specification: infinity ohms
If no wiring malfunction is detected:
- Loosen Knock sensor (KS) and tighten again to 20 Nm.
- Repeat functional check.
- Check control module DTC memory again.
If malfunction is still present:
- Replace Knock sensors (KS) -G61- or -G66-, item 7 or item 17.
- Check DTC memory, repair malfunctions if necessary and then erase DTC memory. Refer to "Displaying and Reading Trouble Codes/With Manufacturer Scan Tool/DTC Memory Checking and Erasing".
Testing and Inspection
- Read readiness code. If the DTC memory has been erased or the Engine Control Module (ECM) was disconnected from battery positive, the readiness code must be generated again. Refer to "Monitors, Trips and/or Drive Cycle (Readiness Codes)/Reading Readiness Code".
Testing and Inspection