A6 Quattro Sedan V6-2.8L (AFC) (1995)
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Knock Sensor: Testing and Inspection
CHECKING KNOCK SENSORS
NOTES:
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Also Refer to On-Board Diagnostics, "Read Measuring Value Block" function 08, display group 015 and/or 016 for functional testing of the
knock sensor. See: Testing and Inspection
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Remove and install with insert 3247.
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Exact compliance with the tightening torque of 20 Nm (15 ft lb) is critical for satisfactory function of the knock sensors.
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Check harness connection for corrosion.
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Use only gold terminals to repair knock sensor harness connectors.
CHECKING KNOCK SENSOR WIRING
3-Pin Connector
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Separate knock sensor harness connectors in engine compartment.
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Check all three terminals at each knock sensor connector for short circuit to each other.
If a connection exists:
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Replace knock sensor.
CHECKING WIRING FROM KNOCK SENSORS TO ECM
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Connect VAG 1598 test box with VAG 1598/11 adapter harness to ECM wiring harness. Refer to Computer and Control Systems, System
Diagnosis, VAG 1598 Pin Out Box Connecting. See: Testing and Inspection/Scan Tool Testing and Procedures/Scan Tool Testing/Scan Tool
Connecting and Initial Checks/Connecting and Testing VAG 1598 Pin Out Box
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Check wiring between sensor and ECM for open circuit or short circuit using wiring diagram.
3-Pin Connector
Terminal assignment of connector:
1 - Ground
2 - Signal wire
3 - Shield
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Check knock sensor 1 -G61- signal wire for continuity between terminal 2 of connector in engine compartment and test box socket 21.
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Specified value: maximum 1.0 ohm
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Check knock sensor 1 -G61- Ground wire for continuity between terminal 1 of connector in engine compartment and test box socket 22.
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Specified value: maximum 1.0 ohm
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Check knock sensor 1 -G61- shielding for continuity between terminal 3 of connector in engine compartment and test box socket 23.
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Specified value: maximum 1.0 ohm
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Check knock sensor 2 -G66- signal wire for continuity between terminal 2 of connector in engine compartment and test box socket 24.
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Specified value: maximum 1.0 ohm
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Check knock sensor 2 -G66- Ground wire for continuity between terminal 1 of connector in engine compartment and test box socket 25.
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Specified value: maximum 1.0 ohm
