Knock Sensor , checking
WARNING: This page is about a different car, the 2007 Audi A4, 2006 Audi A4, and 2005 Audi A4. However, it is still accessible from the selected car via links, so may be relevant.
This procedure is used to diagnose Knock Sensor (KS) 1 G61 and Knock Sensor (KS) 2 G66.
Special tools, testers and auxiliary items required
- Multimeter V.A.G 1526 or equivalent.
- Test Box 105 Pin VAG1598/42.
- Adapter Lead Vag1598/39 VAG1598/39.
- Adapter cable V.A.G 1598/39-1.
NOTE:
- Cylinders 1, 2 are monitored by Knock sensor (KS) 1 -G61-. Cylinders 3,4 are monitored by Knock sensor (KS) 2 -G66-.
- Knock sensors themselves cannot be checked electrically.
- When servicing terminals in the harness connector of knock sensors, use only gold-plated terminals.
- For the knock sensors to function properly, it is important that the tightening torque be exactly 20 Nm.
- Contact surfaces between Knock Sensor (KS) 1 G61 and Knock Sensor (KS) 2 G66 and cylinder block must be free of corrosion, dirt and grease.
Test requirements
- Mounting bolt of Knock Sensor (KS) 1 G61/Knock Sensor (KS) 2 G66 tightened to 20 Nm.
- Fuses for Engine Control Module (ECM) J623 OK.
- Battery voltage at least 12.5 volts.
- All electrical consumers such as, lights and rear window defroster, switched off.
- Vehicles with automatic transmission, shift selector lever into position "P" or "N".
- A/C switched off.
- Ground (GND) connections between engine/transmission/chassis OK.
- Ignition switched off.
Test sequence
- Remove engine cover - arrows -.
NOTE:
- The knock sensor electrical connectors can be identified by color. Knock Sensor (KS) 1 -G61- (Bank 1) is green. Knock Sensor (KS) 2 -G66- (Bank 2) is gray.
- Disconnect the electrical harness connector from Knock Sensor (KS) 1 G61 - 1 - or Knock Sensor (KS) 2 G66 - 2 -.
- Using the Multimeter V.A.G 1526 A or equivalent, check Knock Sensor (KS) 1 G61 or Knock Sensor (KS) 2 G66 electrical connector terminals 1+2 for resistance for a short to each other.
Specified value: 0 Ω (No Continuity).
If the specification is not obtained:
- Replace respective Knock Sensor (KS) 1 G61/Knock Sensor (KS) 2 G66 → 15 - ENGINE - CYLINDER HEAD, VALVETRAIN .
If the specification is obtained:
- Connect the test box 1598/42 to the wiring harness of the Engine Control Module (ECM) J623. → 24 - MULTIPORT FUEL INJECTION (MFI) . The ECM is not connected.
- Using the Test Box 105 Pin VAG1598/42 and Multimeter V.A.G 1526 A or equivalent, check the following wiring connections for an open circuit.
| Component | Terminal | Test box socket |
|---|---|---|
| Knock Sensor (KS) 1 G61 | 1 | 39 |
| 2 | 54 | |
| 3 | 52 | |
| Knock Sensor (KS) 2 G66 | 1 | 9 |
| 2 | 24 | |
| 3 | 52 |
Specified resistance 1.5 Ω max.
- Check the wiring for a short circuit to Battery positive (+) or an open circuit.
- If necessary, repair the wiring connection.
If no malfunctions are found in the wiring:
- Replace the Engine Control Module (ECM) J623 → Engine Control Module (ECM) J623 , replacing .
Assembly is performed in the reverse order of removal, note the following:
Final procedures
After repair work, the following work steps must be performed in the mentioned sequence:
- Check the DTC memory..
- If necessary, erase the DTC memory..
- If the DTC memory was erased, generate readiness code..
- End diagnosis and switch ignition off.