Bendix

The knock sensor can not be tested statically. Therefore the static test is for the wiring harness only and the dynamic test is for the knock sensor only.


STATIC TESTING PROCEDURE:

NOTE: Check that coolant temperature and knock sensor connectors at engine block are not interchanged.
While trouble shooting, always check the wiring, fuses and connectors for good condition and routing. Use the wiring diagrams found in CHASSIS ELECTRICAL DIAGRAMS to supplement your testing efforts.

Accessing Ignition ECU Connector:

1. Turn ignition OFF.
2. Access ignition ECU by removing the panel under left hand side of instrument panel.
3. Remove ECU connector by pushing out the catch and folding out the wire cluster.
4. Check ignition ECU ground connections at intake manifold. They should make good contact.

Removing Protective Cover:

5. Remove connector protective sleeve.
IMPORTANT: ^ Never check connections from the front. Connectors can get damaged and worsen the problem.
^ Check connections through the holes in the connector.
^ Connection pin numbers are printed on the connector side.

Checking Terminal Pins:

6. Check that terminal contacts have been pushed down evenly in connector.
7. If any connectors have been pushed down to far, poor connection may result.

Checking Battery Supply:

8. Check main power supply by connecting a voltmeter between pin 5 (brown) in ECU connector and ground.

Reading: approx. 12 volts

9. If no voltage registers, check wire between ECU and fuse-box located behind the center console ash tray. Check fuse #1 and wiring to battery (incl. battery terminals). Repair as necessary.

Checking Knock Sensor Wiring:

10. Check wiring by removing the connector from the knock sensor. Install a bridge wire between terminal 1 and 2.

Testing Knock Sensor:

11. Connect an ohmmeter between pin 12 (black) and 13 (green) at ECU connector.

Reading: 0 ohm

12. If resistance is to high, remove bridge wire and check each wire separately for resistance.
a. Replace damaged wire(s).
b. If wires are not damaged, replace knock sensor.
13. After testing, disconnect all test equipment, reconnect all connectors (including the ECU connector) and remount all panels.


DYNAMIC TESTING PROCEDURE:

The sensor can only be tested dynamically with the use of an oscilloscope.

1. Turn ignition ON.
2. Probe terminals #1 and #2 at knock sensor.

Typical Knock Sensor Signal:

3. Tap on the engine block, near the sensor, with a small hammer or wrench.
4. Oscilloscope should show a wave pattern similar to the one shown in the image.
a. If pattern is correct, knock sensor is working properly.
b. If pattern is incorrect, replace and retest with new sensor.
5. Turn ignition OFF and disconnect all test equipment.