Knock Sensor 4
Special tools, testers and auxiliary items required
- Multimeter.
- Wiring diagram.
Test requirements
- The mounting bolt of Knock Sensor 4 G199 tightened to 20 Nm.
- The Motronic Engine Control Module (ECM) J623 fuses 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 procedure
- Perform a preliminary check to verify the customers complaint. Refer to → General Diagnosis .
Start diagnosis
- Remove the intake manifold. Refer to → 24 - MULTIPORT FUEL INJECTION (MFI) .
- Disconnect the brown Knock Sensor 4 G199 electrical harness connector - 1 -.
Checking internal resistance
- Using a Multimeter, check the Knock Sensor 4 G199 terminals 1 to 2 for an internal short.
Specified value: ∞ (Infinity).
If the specified value was not obtained:
- Replace Knock Sensor 4 G199. Refer to → 24 - MULTIPORT FUEL INJECTION (MFI) .
If the specified value was obtained:
Checking wiring
If the manufacturers test box is being used. Perform the following step.
- Install the test box. Refer to → 24 - MULTIPORT FUEL INJECTION (MFI) .
If the manufacturers test box is not being used. Perform the following step.
- Remove the Motronic Engine Control Module (ECM) J623. Refer to → Engine Control Module, Removing and Installing .
- Using a Multimeter, check the Knock Sensor 4 G199 electrical harness connector to the electrical harness connector T60 for an open circuit.
| Knock Sensor 4 G199 electrical harness connector terminals | Motronic Engine Control Module (ECM) J623 electrical harness connector T60 terminals or test box sockets |
|---|---|
| 1 | 53 |
| 2 | 38 |
| 3 | 52 (Shield) |
Specified value: 1.5 Ω Max.
If the specified value was not obtained:
- Check the wiring connection for an open circuit, short circuit to Battery (+) or Ground (GND).
- Check the wiring connection for damage, corrosion, lose or broken terminals.
- If necessary, repair the faulty wiring connection.
If no malfunction is found in the wiring and the resistance was not OK:
- Replace Knock Sensor 4 G199. Refer to → 24 - MULTIPORT FUEL INJECTION (MFI) .
If no malfunction is found in the wiring and the resistance was OK:
- Replace the Motronic Engine Control Module (ECM) J623. Refer to → Engine Control Module, Removing and Installing .
Assembly is performed in the reverse order of removal.
- Install the intake manifold. Refer to → 24 - MULTIPORT FUEL INJECTION (MFI) .
Final procedures
After repair work, the following work steps must be performed in the following sequence:
- Check the DTC memory.
- If necessary, erase the DTC memory. Refer to Diagnostic Mode 04 - Reset/Delete Diagnostic Data .
- If the DTC memory was erased, generate readiness code. Refer to Readiness Code .
- End of diagnosis.