Knock Sensor: Testing and Inspection

DIGIFANT II







Knock Sensor - Checking

Requirements

- Engine oil temperature must be a minimum of 80°C (176°F) and radiator cooling tan must come on at least once.
- Ignition timing must be within specifications.
- Connect VW 1367 (ignition switched OFF).
- Start the engine and raise speed to a minimum of 2100 RPM four times, letting the throttle close each time.

Note: This clears the fault memory in the E.C.U. and cancels the hot-start idle increase function. This must be repeated each time the vehicle is stopped and re-started during the test procedure.

- Disconnect the coolant temperature sensor.
- Increase the engine speed to 2300 ± 50 RPM and record ignition timing.
- Reconnect the coolant temperature sensor.
- Briefly raise engine speed above 3000 RPM to store the knock sensor information in the E.C.U.
- Increase engine speed to 2300 ± 50 RPM and re-check ignition timing.
- Ignition timing must advance by 30° ± 3° from initial setting.

If timing does not advance by 30° ± 3° from initial setting:

- Check knock sensor torque and wiring to Digifant E.C.U. using the wiring diagram.
- Torque: 15 Nm - 25 Nm (11-18 ft-lbs.)

If knock sensor torque and wiring are OK

- Check the engine coolant temperature sensor and wiring to the Digifant E.C.U

If the coolant temperature sensor and wiring are OK:

- Replace the knock sensor or,
- Replace the Digifant E.C.U.