With Manufacturer's Scan Tool
Knock Sensors (KS), Checking
NOTE:
- It is extremely important to keep to the tightening torque of 20 Nm to ensure the Knock Sensors (KS) perform perfectly.
- Knock Sensors (KS) 1 -G61- and 2 -G66- have a direct 2-pin connector and consequently no terminal for the shielding in the connector
- Only gold-plated terminals may be used when servicing the Knock Sensor (KS) connector terminals.
- Contact surfaces between Knock Sensor (KS) and cylinder block must be free of corrosion, dirt and grease.
Special tools, test equipment and auxiliary items
- VAG 1551 scan tool (or VAG 1552 mobile scan tool) with VAG 1551/3B cable
- VAG 1598/31 test box
- VAG 1526 hand multimeter or VAG 1715 multimeter
- VAG 1594 adapter set
- Electrical Wiring Diagrams
Test conditions
- On Board Diagnostic (OBD) must have recognized a malfunction in one or both Knock Sensors (KS, Checking and Erasing DTC Memory. Reading Diagnostic Trouble Codes
- Engine Coolant Temperature must be at least 85 °C, see display group 28, display zone 3
Checking function
- Connect VAG 1551 scan tool (or VAG 1552 scan tool). Start engine and select "Address word" 01 of Engine Control Module. Engine must be running at idle speed. Connecting scan tool and selecting Engine Control Module. [1][2][3]Connecting VAG 1551 Scan Tool
Indicated on display
Rapid data transfer HELP
Select function XX
- Press buttons -0- and -8- for the function "Read measured value block" and confirm entry with -Q- button.
Indicated on display
Read measured value block
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 (1-4 = Display zones)
Read measured value block 28 ->
1 2 3 4
NOTE: Checking the Knock Sensors (KS) must be performed during a road test because the Knock Sensors (KS) OBD is not activated until the engine speed exceeds 2000 RPM and the engine is loaded by more than 40 %.
- Perform a road test and check knock control specifications on display (display zone 4).
Observe the valid safety precautions when road testing.
If the specification is obtained:
- Press -> button.
- Press buttons -0- and -6- for function "End output" and confirm entry with -Q- button.
- Switch off ignition.
Continuation:
If the specifications are not obtained:
- Press -> button.
- Press buttons -0- and -6- for function "End output" and confirm entry with -Q- button.
- Switch off ignition.
Checking resistance of Knock Sensors (KS)
- Disconnect 2-pin harness connector to Knock Sensor (KS) 1 -G61- (item no. 1) and/or 2-pin harness connector to Knock Sensor (KS) 2 -G66- (item no. 2).
- Measure resistance between the terminals 1 + 2 at connections to Knock Sensors (KS).
Specification: Infinity Ohms
If the specification is not obtained:
- Replace Knock Sensors (KS) -G61- or -G66-, item 12 or item 13.
- Check DTC Memory, if necessary, repair any malfunctions and then Erase DTC Memory , Checking and Erasing DTC Memory. Reading Diagnostic Trouble Codes
- Read readiness code. If DTC memory has been erased or Engine Control Module was disconnected from battery positive, readiness code must be generated again.
Monitors, Trips, Drive Cycles and Readiness Codes
Monitors, Trips, Drive Cycles and Readiness Codes
If the specification is obtained:
- Check wiring.
Checking wiring
- Remove inner plenum chamber cover, left.
- Connect VAG 1598/31 test box to control module wiring harness. Engine Control Module is not connected by this action.
- Check wiring between test box and 2-pin connector for open circuit using Electrical Wiring Diagrams.
Knock Sensor -G61-: -G66-:
Contact 1 + socket 106 107
Contact 2 + socket 99 99
Wire resistance: Max. 1.5 Ohms
- Additionally check wires at socket 99 for short to sockets 106 and 107.
Specification: Infinity Ohms
If no malfunctions in wiring are detected:
- Loosen Knock Sensor (KS) and tighten again to 20 Nm.
- Perform a road test again and check knock control specifications on display.
Observe the valid safety precautions when road testing.
During the road test Engine Coolant Temperature must exceed 85°C
When the temperature is reached, these operating conditions must be obtained several times:
- Idle
- Part throttle
- Full throttle
- Overrun
- At full throttle the engine speed must exceed 3500 RPM.
- Again check control module DTC memory.
If the malfunction is still present:
- Replace Knock Sensors (KS) -G61- or -G66-, item 12 or item 13.
- Check DTC Memory, if necessary, repair any malfunctions and then Erase DTC Memory, Checking and Erasing DTC Memory. Reading Diagnostic Trouble Codes
- Read readiness code. If DTC memory has been erased or Engine Control Module was disconnected from battery positive, readiness code must be generated again.
Monitors, Trips, Drive Cycles and Readiness Codes
Monitors, Trips, Drive Cycles and Readiness Codes