740 L4-2.3L SOHC VIN 88 B230F (1985)
^ 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 Pins 12 And 13
8.
Check wiring by removing the connector from the knock sensor. Install a bridge wire between terminal 1 and 2.
9.
Connect an ohmmeter between pin 12 (brown) and 13 (green) at ECU connector.
Reading: 0 ohm
10.
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 or if possible, check knock sensor as described below under DYNAMIC TESTING
PROCEDURE. Replace as necessary.
11.
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.