Knock Sensor: Testing and Inspection

2002 Hyundai XG 350 V6-3.5LSECTION Testing and Inspection



KNOCK SENSOR
The knock sensor is a piezoelectric device attached to the cylinder block that senses pressure from engine knocking conditions. This vibrational pressure is then converted into a voltage signal which is delivered as output. If engine knock occurs, ignition timing is retarded to suppress it.

Circuit Diagram:






Troubleshooting Procedures:






TROUBLESHOOTING HINTS
1. The MIL is ON or the DTC is displayed on the HI-SCAN PRO under the following condition:
- When the knock sensor signal is not detected, even though the engine is in an overload condition.
- When the knock sensor signal is abnormally low.


Harness Inspection Procedures 1 - 2:









SENSOR INSPECTION
1. Disconnect the knock sensor connector.
2. Measure the resistance between terminals 2 and 3.
Standard value : about 5 M Ohms [at 20 °C (68 °F)]

3. If the resistance is zero, replace the knock sensor.
Knock sensor: 16 - 28 Nm (160 - 250 kg.cm, 11.8 - 18.4 lb.ft)

4. Measure the capacitance between the terminal 2 and 3.
Standard value : 800 - 1600 pF
RENDER: 1.0x

NO RELATED

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When to See a Mechanic

Stop DIY work and contact a certified mechanic immediately if any of the following apply:

  • β€’ You smell fuel, burning insulation, or see smoke.
  • β€’ Brakes feel soft, pull hard to one side, or make grinding noises.
  • β€’ The engine overheats, stalls repeatedly, or misfires under load.
  • β€’ You are missing required tools, torque specs, or safe lifting equipment.
  • β€’ You are not confident in the next step or safety outcome.