Knock Sensor: Testing and Inspection
Checking Knock SensorsNotes:
^ Also Refer to On Board Diagnostic, "Read Measuring Value Block" function 08, display group 015 and/or 016 for functional testing of the knock sensor. Testing and Inspection
^ Also Refer to Oscilloscope Patterns and Waveforms, Knock Sensor Test
^ Remove and install with insert 3247.
^ Exact compliance with the tightening torque of20 Nm (15 ft lb) is critical for satisfactory function of the knock sensors.
^ Check harness connection for corrosion
^ Use only gold terminals to repair knock sensor harness connectors.
Checking Knock Sensor Wiring
3-Pin Connector:
- Separate knock sensor harness connectors in engine compartment.
- Check all three terminals at each knock sensor connector for short circuit to each other.
- If a connection exists, replace knock sensor.
Checking wiring from knock sensors to ECM
- Connect VAG 1598 test box with VAG 1598/11 adapter harness to ECM wiring harness. Connecting and Testing VAG 1598 Pin Out Box
- Check wiring between sensor and ECM for open circuit or short circuit using wiring diagram.
3-Pin Connector:
Terminal assignment of connector:
1 - Signal wire
2 - Ground
3 - Shield
- Check knock sensor 1 -G61- signal wire for continuity between terminal 2 of connector in engine compartment and test box socket 21.
^ Specified value: maximum 1 (ohm)
- Check knock sensor 1 -G61- Ground wire for continuity between terminal 1 of connector in engine compartment and test box socket 22.
^ Specified value: maximum 1 (ohm)
- Check knock sensor 1 -G61- shielding for continuity between terminal 3 of connector in engine compartment and test box socket 23.
^ Specified value: maximum 1 (ohm)
- Check knock sensor 2 -G66- signal wire for continuity between terminal 2 of connector in engine compartment and test box socket 24.
^ Specified value: maximum 1 (ohm)
- Check knock sensor 2 -G66- Ground wire for continuity between terminal 1 of connector in engine compartment and test box socket 25.
^ Specified value: maximum 1 (ohm)
- Check knock sensor 2 -G66- shielding for continuity between terminal 3 of connector in engine compartment and test box socket 26.
^ Specified value: maximum 1 (ohm)
If specified values are not obtained:
- Repair break in wiring and/or short circuit between sensor connector and ECM connector B.
Knock sensor I (right cyl. bank):
Blue sensor ECM connector B
connector terminal terminal
1 (signal) 2
2 (Ground) 1
3 (shield) 3
Knock sensor 2 (left cyl. bank):
Blue sensor ECM connector B
connector terminal terminal
1 (signal) 5
2 (Ground) 4
3 (shield) 6