Knock Sensors, Checking

Knock Sensor, Checking

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 ohm (No Continuity).

If the specification is not obtained:
- Replace respective Knock Sensor (KS) 1 G61 / Knock Sensor (KS) 2 G66.

If the specification is obtained:
Connect the test box 1598/42 to the wiring harness of the Engine Control Module (ECM) J623. 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 Ohms 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.

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:
1. Check the DTC memory.
2. If necessary, erase the DTC memory.
3. If the DTC memory was erased, generate readiness code.

- End diagnosis and switch ignition off.